The famed boxer joined fellow guests including David Beckham, Sir Christopher Lee and rocker Bob Geldof at the Sports for Peace fundraiser at the British capital's the Victoria and Albert Museum but looked frail as he arrived in a wheelchair.
However, Ali made sure he got to his feet to wave at the crowd during the event, which raised funds for the Muhammad Ali Foundation and Michael J. Fox Foundation for Parkinson's Disease.
Geldof said, "Muhammad Ali was intensely political, and changed the whole agenda (of charity work). He did it with the same bravery he did in the ring."
Ali's brother Rahman fuelled speculation the sportsman will be included in the Olympic Games opening ceremony on Friday (27Jul12) by telling reporters, "There's a possibility. He makes decisions at the last minute."
The event also included an auction to raise funds for good causes, with prizes including tickets to the Olympics opening ceremony, a pair of earrings designed by Hollywood actress Angelina Jolie, and a weekend of driving with Formula One ace Lewis Hamilton.