Muhammad Ali At Opening Ceremony: 'The Greatest' Helps Kick Off London Olympics (VIDEO)

The Greatest returned for another round at the Olympics.

At age 70 and stricken with Parkinson's disease, iconic boxer Muhammad Ali made a brief but memorable appearance at the Opening Ceremony for the 2012 London Olympics late in the program during the presentation of the Olympic flag.

In the days leading up to director Danny Boyle's production, rumors swirled about the special guests possibly involved in the Opening Ceremony, including Ali.

The 1960 gold medalist produced perhaps one of the most iconic Opening Ceremony moments of all time when he lit the Olympic Cauldron at the onset of the Atlanta Games in 1996. In 2012, Ali emerged in a white suit when it was time to present the Olympic flag.

Earlier this week, Ali was the guest of honor at the Sports for Peace fundraiser. The Olympic kick-off gala raised money for the Muhammad Ali Center and for research into Parkinson's disease.

When Ali's brother Rahaman was asked whether the boxing legend would play a role in Friday's opening ceremony, he merely said it was possible and that Muhammad tends to make "decisions at the last minute."