U.S. Ambassador to Japan Caroline Kennedy attends a calligraphy lesson at Mangokuura Elementary School in Ishinomaki, Miyagi Prefecture, northeastern Japan, Nov. 25, 2013.

U.S. First Lady Michelle Obama watches a Noh performance by local college students, with monk of Kiyomizu-dera Buddhist temple, Eigen Onishi, far left, U.S. Ambassador to Japan Caroline Kennedy and her son John Schlossberg, far right, at the temple in Kyoto, western Japan, March 20, 2015. Noh is a form of classical Japanese musical drama.

Caroline Kennedy smiles during a presentation ceremony for the "Profile in Courage Award," Monday, May 24, 2004, at the John F. Kennedy Presidential Library and Museum in Boston.

Caroline was 11 months when this photograph was taken with her mother and father, then a U.S. senator from Massachusetts.

Sen. John F. Kennedy, Democratic presidential nominee, carries his daughter, Caroline, 2, en route to a plane at Hyannis, Mass., on Aug. 29, 1960.

Caroline Kennedy, 3, holds the hand and foot of her baby brother, John F. Kennedy Jr., in 1961 in Palm Beach, Fla.

President John F. Kennedy and family pose outside the Palm Beach, Fla., home of the president's father after a private Easter Service on April 14, 1963. From left are First Lady Jacqueline Kennedy, John Jr., 2, President Kennedy, and Caroline, 5.

President Kennedy claps time as his children Caroline, 4, and John Jr., 1, dance in the president's White House office in October 1962.

President John F. Kennedy with his daughter Caroline in the Oval Office at the White House.

President John F. Kennedy shakes hands with Japanese Prime Minister Hayato Ikeda, at right, at the White House in Washington, June 21, 1961.

Today, Kennedy's daughter, Caroline, serves as U.S. ambassador to Japan.

Three-year-old John F. Kennedy Jr. salutes his father's casket in Washington on Nov. 25, 1963, three days after the president was assassinated in Dallas. Widow Jacqueline Kennedy, center, and daughter Caroline Kennedy are accompanied by the late president's brothers Sen. Edward Kennedy, left, and Attorney General Robert Kennedy.

Caroline, right, Courtney, center, and Kerry Kennedy are seen in a pup tent at a campsite, May 9, 1967. Courtney and Kerry are Robert Kennedy's children.

Aristotle Onassis and his new wife, Jacqueline Kennedy, with her daughter, Caroline, left, walk back to his yacht after their wedding on Skorpios Island, Greece on Oct. 20, 1968.

Caroline Kennedy, left, and her mother, Jacqueline Kennedy Onassis, right, smile following Caroline's graduation ceremony at Harvard University in Cambridge, Massachusetts, on June 5, 1980.

Caroline Kennedy and her brother John Kennedy, Jr. stand together as they follow the casket bearing the remains of their mother Jacqueline Kennedy Onassis out of St. Ignatius Loyola Church in New York following a funeral Mass, May 24, 1994.

Caroline Kennedy Schlossberg and her husband, Edwin Schlossberg, far left, arrive at Washington's National Cathedral to attend the funeral service for former President Ronald Reagan, Friday, June 11, 2004.

Caroline Kennedy, daughter of slain President John F. Kennedy, looks up to see an old film of herself as a child with her father, at the John F. Kennedy Presidential Library and Museum in Boston,  March 7, 2005.