
President Barack Obama, Prince William and first lady Michelle Obama talk with Prince George at Kensington Palace on April 22, 2016, in London.

Obama and the first lady are greeted by Queen Elizabeth II and Prince Phillip after landing by helicopter at Windsor Castle for a private lunch on April 22, 2016.

Philip drives the President, the first lady and Elizabeth from the helicopter into Windsor Castle after the Obama's arrived for a private lunch in Windsor, England, on April 22, 2016.

Elizabeth, the President, the first lady and Philip pose for a photograph in the Oak Room ahead of a private lunch at Windsor Castle on April 22, 2016.

The President, the first lady and the Duke and Duchess of Cambridge meet in London's Buckingham Palace on May 24, 2011.

President Barack Obama meets with Prince Harry in the Oval Office on October 28, 2015.

Queen Elizabeth II poses with the President, the first lady and Prince Philip, Duke of Edinburgh, in the Music Room of Buckingham Palace ahead of a State Banquet on May 24, 2011.

Jill Biden, Prince Harry and Michelle Obama at the Joining Forces Invictus Games 2016 Event at the Wells Fields House on October 28, 2015, in Fort Belvoir, Va.

President Barack Obama sees off Queen Elizabeth II, as the Duke of Edinburgh and the first lady follow after a reciprocal dinner at the Winfield House in London, on May 25, 2011.

Queen Elizabeth II speaks with President Barack Obama during a group photo of world leaders attending the D-Day 70th Anniversary ceremonies at Chateau de Benouville in Benouville, France, on June 6, 2014.