By Elise Viebeck - 07/23/12 07:24 PM EDT
The afternoon event will take place at the U.S. ambassador's residence in London and involve 1,000 young people — a mix of U.K. natives and the children of American servicemembers based in Britain.
The Olympics "serve as a powerful opportunity to send another message to the kids in this country about the importance of staying fit," Obama said.
According to a White House memo, the afternoon will feature U.S. Olympians and famous athletes such as soccer star David Beckham.
Obama will also meet with Samantha Cameron, the British Prime Minister's wife, during her time in London, as well as attend a reception hosted by Queen Elizabeth II.