More than 300 people serenaded boxing icon Muhammad Ali with a rousing rendition of "Happy Birthday" at a lavish $1,000-a-plate fundraiser and party in his Kentucky hometown.

Ali, who is one of the world's most recognizable sportsman, turns 70 on Tuesday.

The former three-time world heavyweight champ now suffers from Parkinson's disease which doctors have said could be a result of his boxing career.

The fund-raiser was held at the Muhammad Ali Center in Louisville and is part of the facility's "Seven Days for Seven Decades" programme of community activities.

Ali moved slowly but at times walked on his own as he mingled and waved to attendees. When he was not walking by himself, he was assisted by his wife Lonnie.

Besides relatives, the guest list included Ali's former trainer Angelo Dundee and three American hikers who were once jailed in Iran. Ali, who is Muslim, had pushed the Iran government for their release.

Rock star John Mellencamp, whose son is a boxer, performed at the event.

Ali, who was born Cassius Clay in Louisville on January 17, 1942, owns homes in Arizona and Michigan as well as in Louisville.

In November, the heavyweight great was briefly hospitalized in Phoenix, where doctors treated him for dehydration.

That came a few days after Ali attended the funeral of his old rival Joe Frazier, who died of liver cancer in Philadelphia on November 8.

Ali has tried to use his public stature to raise awareness about his illness and campaign for research funding.

He has also continued to involve himself in various charitable ventures and campaigned for boxing reform.

The Muhammad Ali Center -- which opened in November 2005 -- is a six-story cultural center that celebrates his life and career, including his legendary fights against Frazier and George Foreman.