Princess Christina and Japan's Tasuku Honjo, winner of the Nobel Prize in Physiology or Medicine, attend the Nobel dinner in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

Princess Christina and Japan's Tasuku Honjo, winner of the Nobel Prize in Physiology or Medicine, attend the Nobel dinner in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

Princess Christina and Japan's Tasuku Honjo, winner of the Nobel Prize in Physiology or Medicine, attend the Nobel dinner in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

Princess Christina and Japan's Tasuku Honjo, winner of the Nobel Prize in Physiology or Medicine, attend the Nobel dinner in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

Princess Christina and Japan's Tasuku Honjo, winner of the Nobel Prize in Physiology or Medicine, attend the Nobel dinner in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

The Nobel dinner is held in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

The Nobel dinner is held in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

The Nobel dinner is held in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

The Nobel dinner is held in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

The Nobel dinner is held in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

Around 1,300 people attend the Nobel Banquet held at the Stockholm City Hall in the Swedish capital on Dec. 10, 2018, after the award ceremony. (Kyodo via AP Images) ==Kyodo

Around 1,300 people attend the Nobel Banquet at the Stockholm City Hall in the Swedish capital on Dec. 10, 2018. Seen on the left lane and fifth from the bottom is Japanese Nobel Prize winner in physiology or medicine, Tasuku Honjo. (Kyodo via AP Images) ==Kyodo

Photo shows the dessert served at the Nobel banquet held at the Stockholm City Hall after the award ceremony in the Swedish capital on Dec. 10, 2018. (Kyodo via AP Images) ==Kyodo

Photo shows the appetizer served at the Nobel banquet held at the Stockholm City Hall after the award ceremony in the Swedish capital on Dec. 10, 2018. (Kyodo via AP Images) ==Kyodo

Photo shows the main dish served at the Nobel banquet held at the Stockholm City Hall after the award ceremony in the Swedish capital on Dec. 10, 2018. (Kyodo via AP Images) ==Kyodo

Around 1,300 people attend the Nobel Banquet at the Stockholm City Hall in the Swedish capital on Dec. 10, 2018. (Kyodo via AP Images) ==Kyodo

Physics 2018 Nobel laureate Frances H. Arnold and Prince Daniel of Sweden arrive for the Nobel Prize banquet in Stockholm City Hall, Sweden, Monday Dec. 10, 2018. (Fredrik Sandberg/TT via AP)

US chemical engineer and co-laureate of the 2018 Nobel Prize in Chemistry Frances Arnold (L) talks with Prince Daniel of Sweden during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Physics 2018 Nobel laureate Donna Strickland and King Carl Gustaf of Sweden arrive for the Nobel Prize banquet in Stockholm City Hall, Sweden, Monday Dec. 10, 2018. (Fredrik Sandberg/TT via AP)

Canadian physicist and co-laureate of the 2018 Nobel Prize in Physics Donna Strickland (L) and King Carl Gustaf of Sweden look on during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Queen Silvia of Sweden (R) and French physicist and co-laureate of the 2018 Nobel Prize in Physics Gerard Mourou look on during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Queen Silvia of Sweden looks on during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Physics 2018 Nobel laureate Gerard Mourou and Princess Sofia of Sweden arrive for the Nobel Prize banquet in Stockholm City Hall, Sweden, Monday Dec. 10, 2018. (Janerik Henriksson/TT via AP)

Princess Sofia of Sweden (L) and French physicist and co-laureate of the 2018 Nobel Prize in Physics Gerard Mourou arrive to the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Princess Sofia of Sweden (L) and French physicist and co-laureate of the 2018 Nobel Prize in Physics Gerard Mourou arrive to the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Princess Sofia of Sweden (L) and French physicist and co-laureate of the 2018 Nobel Prize in Physics Gerard Mourou look on during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Princess Sofia of Sweden looks on during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Chemistry laureate George P. Smith and Crown Princess Victoria of Sweden arrive for the Nobel Prize banquet in Stockholm City Hall, Sweden, Monday Dec. 10, 2018. (Fredrik Sandberg/TT via AP)

Princess Sofia of Sweden looks on during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

A torchlight procession passes below in honour of the 2018 Nobel Peace Prize laureates, Dr. Denis Mukwege from Congo, left, and Nadia Murad from Iraq in Oslo, Norway, Monday Dec. 10, 2018. Dr. Denis Mukwege and Nadia Murad received the Nobel Peace Prize recognising their efforts to end the use of sexual violence as a weapon of war and armed conflict. (Fredrik Hagen/NTB Scanpix via AP)

A torchlight procession passes below in honour of the 2018 Nobel Peace Prize laureates, Dr. Denis Mukwege from Congo, left, and Nadia Murad from Iraq in Oslo, Norway, Monday Dec. 10, 2018. Dr. Denis Mukwege and Nadia Murad received the Nobel Peace Prize recognising their efforts to end the use of sexual violence as a weapon of war and armed conflict. (Heiko Junge/NTB Scanpix via AP)

The head table at the Nobel Prize banquet in Stockholm City Hall, Sweden, on Monday Dec. 10, 2018. (Fredrik Sandberg/TT via AP)

The Blue Hall, with the head table in the center, Nobel Prize banquet in Stockholm City Hall, Sweden, on Monday Dec. 10, 2018. (Fredrik Sandberg/TT via AP)

Princess Christina and Japan's Tasuku Honjo, winner of the Nobel Prize in Physiology or Medicine, attend the Nobel dinner in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

Princess Christina and Japan's Tasuku Honjo, winner of the Nobel Prize in Physiology or Medicine, attend the Nobel dinner in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

Japan's Tasuku Honjo, winner of the Nobel Prize in Physiology or Medicine, attends the Nobel dinner in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

Princess Christina and Japan's Tasuku Honjo, winner of the Nobel Prize in Physiology or Medicine, attend the Nobel dinner in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

The Nobel dinner is held in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

The Nobel dinner is held in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

The Nobel dinner is held in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

The Nobel dinner is held in the City Hall of Stockholm, Sweden, December 10, 2018. ( The Yomiuri Shimbun via AP Images )

Swedish Prime Minister Stefan Loefven (R) arrive to the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Japanese immunologist and co-laureate of the 2018 Nobel Prize in Physiology or Medicine Tasuku Honjo and Princess Christina of Sweden arrive to the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

US immunologist and co-laureate of the 2018 Nobel Prize in Physiology or Medicine James Allison (R) and Sweden Prime Minister's wife Ulla Loefven arrive to the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

(L-R) US biologist and co-laureate of the 2018 Nobel Prize in Chemistry George Smith, Princess Christina of Sweden and Japanese immunologist and co-laureate of the 2018 Nobel Prize in Physiology or Medicine Tasuku Honjo talk during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Guests take their sits at the start of the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Nobel prize laureates Congolese gynecologist Denis Mukwege (L) and Iraqi Yazidi-Kurdish human rights activist Nadia Murad wave people holding candles during a torchlight procession in Oslo downtown, Norway on December 10, 2018. (Photo by Heiko JUNGE / NTB SCANPIX / AFP) / Norway OUT

Princess Sofia of Sweden talks with British biochemist and co-laureate of the 2018 Nobel Prize in Chemistry Gregory Winter during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Princess Sofia of Sweden talks with British biochemist and co-laureate of the 2018 Nobel Prize in Chemistry Gregory Winter during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Queen Silvia of Sweden (R) talks with French physicist and co-laureate of the 2018 Nobel Prize in Physics Gerard Mourou during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Queen Silvia of Sweden (R) talks with French physicist and co-laureate of the 2018 Nobel Prize in Physics Gerard Mourou during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Princess Sofia of Sweden talks with British biochemist and co-laureate of the 2018 Nobel Prize in Chemistry Gregory Winter during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Crown Princess Victoria of Sweden is seen during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Crown Princess Victoria of Sweden reacts during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

Crown Princess Victoria of Sweden is seen during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

David Howell Evans, Guitarist of U2, is seen during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

David Howell Evans, Guitarist of U2, is seen during the Nobel Prize banquet in Stockholm City Hall, Sweden on December 10, 2018. (Photo by Jonathan NACKSTRAND / AFP)

This picture taken on December 10, 2018 shows a general view of the Nobel Prize banquet and its guests in the Stockholm City Hall, Sweden. (Photo by Jonathan NACKSTRAND / AFP)

This picture taken on December 10, 2018 shows a general view of the Nobel Prize banquet and its guests in the Stockholm City Hall, Sweden. (Photo by Jonathan NACKSTRAND / AFP)

This picture taken on December 10, 2018 shows a general view of the Nobel Prize banquet and its guests in the Stockholm City Hall, Sweden. (Photo by Jonathan NACKSTRAND / AFP)

This picture taken on December 10, 2018 shows a general view of the Nobel Prize banquet and its guests in the Stockholm City Hall, Sweden. (Photo by Jonathan NACKSTRAND / AFP)

This picture taken on December 10, 2018 shows a general view of the Nobel Prize banquet and its guests in the Stockholm City Hall, Sweden. (Photo by Jonathan NACKSTRAND / AFP)

This picture taken on December 10, 2018 shows a general view of the Nobel Prize banquet and its guests in the Stockholm City Hall, Sweden. (Photo by Jonathan NACKSTRAND / AFP)

This picture taken on December 10, 2018 shows a general view of the Nobel Prize banquet and its guests in the Stockholm City Hall, Sweden. (Photo by Jonathan NACKSTRAND / AFP)

This picture taken on December 10, 2018 shows waiters bringing the dessert during the Nobel Prize banquet in the Stockholm City Hall, Sweden. (Photo by Jonathan NACKSTRAND / AFP)

This picture taken on December 10, 2018 shows waiters bringing the dessert during the Nobel Prize banquet in the Stockholm City Hall, Sweden. (Photo by Jonathan NACKSTRAND / AFP)

This picture taken on December 10, 2018 shows dancers performing before the dessert parade during the Nobel Prize banquet in the Stockholm City Hall, Sweden. (Photo by Jonathan NACKSTRAND / AFP)

This picture taken on December 10, 2018 shows dancers performing before the dessert parade during the Nobel Prize banquet in the Stockholm City Hall, Sweden. (Photo by Jonathan NACKSTRAND / AFP)

TOPSHOT - This picture taken on December 10, 2018 shows a general view of the Nobel Prize banquet and its guests in the Stockholm City Hall, Sweden. (Photo by Jonathan NACKSTRAND / AFP)