WASHINGTON, DC - MARCH 19: Prince Charles, Prince of Wales smiles with President of the United States of America Barack Obama in the Oval Office on the third day of a visit to the United States on March 19, 2015 in Washington, DC. The Prince and Duchess are in Washington as part of a Four day visit to the United States. (Photo by Chris Jackson/Getty Images)

WASHINGTON, DC - MARCH 19:  Prince Charles, Prince of Wales smiles with President of the United States of America Barack Obama in the Oval Office on the third day of a visit to the United States on March 19, 2015 in Washington, DC. The Prince and Duchess are in Washington as part of a Four day visit to the United States.  (Photo by Chris Jackson/Getty Images)