Fox defends political advert

Michael J. Fox has hit back at claims his appearance on a political advert was an act.

The actor, who has advanced Parkinson's disease, appeared on a 30-second commercial in the US to urge people to support stem cell research.

Speaking in an advert for Claire McCaskill, a Democrat in Missouri who supports the research and is challenging Republican senator Jim Talent for his seat in the state, Fox says: "They say all politics is local, but that's not always the case. What you do in Missouri matters to millions of Americans. Americans like me."

Fox, who battled with the disease while it was still in its early stages during production of Spin City, was moving uncontrollably during the piece.

The ad had a moving effect on many and led to some unexpected outbursts regarding the seriousness of Fox's condition.

Rightwing US radio host Rush Limbaugh accused Fox of playing up for the cameras.

But Fox has defended his stance on stem cell research, which could aid in finding a cure for the neurological disease, and his current condition.

"The irony is that I was too medicated," he said.

"Because the thing aboutbeing symptomatic is that it's not comfortable. No one wants to be symptomatic; it's like being hit with a hammer."

Fox, who starred in the blockbuster franchise Back to the Future, said that without appropriate medication he is unable to function.

"At this point now, if I didn't take medication I wouldn't be able to speak," he said.

The actor was diagnosed with Parkinson's in 1991. He didn't make his illness public until 1998.