Fox, who starred in the Back To The Future film trilogy, will appear as a new character in the hugely successful US TV series Rescue Me.

He was offered the recurring role by Denis Leary, star and co-creator of the comedy drama.

Fox, 47, revealed his condition in 1998 and two years later said he was semi-retiring from acting. 

Now friends say a new medication regime has dramatically improved his health. 

One said yesterday: “Michael is thrilled about the chance of appearing regularly in a show again.”