Michael J Fox is heading Back To The Future for a fourth time-travelling movie.

The actor, who suffers from Parkinson's disease, admits he's in negotiations for a final film in the series - but only if they make his character as old as he is in real life.

The former SPIN CITY star wants to take over Christopher Lloyd's eccentric scientist character, DOC, in the sequel

He tells movie website Moviehole.net, "The only way it would work would be if I played Doc. I'm 44-years-old now and I'm not interested in running around on skateboards!

"I think after 1, 2 and 3 we all kind of felt we had done it. And I think if they did it again now they would do it with a younger cast and just do a different realisation of it, which would be fun."