Ian McKellen, Gandalf in Lord of the Rings, falls off stage in London

Actor Ian McKellen is expected to make a full recovery after he toppled off a London stage during a fight scene and was hospitalised, producers have said.

McKellen, 85, was in “good spirits” after doctors said a scan showed he was expected to fully recover from the fall on Monday night, a spokesperson for the production at the Noel Coward Theatre said.

Tuesday's performance was canceled but McKellen was expected to be back onstage Wednesday, producers said.

The stage and screen veteran, who played Gandalf in the “Lord of the Rings” films, cried out in pain after the fall, according to a BBC journalist at the theatre.

McKellen was playing the roguish John Falstaff in “Player Kings,” an adaptation of William Shakespeare's two “Henry IV” history plays, directed by Robert Icke.

Theatregoers were startled when McKellen lost his footing and fell off the stage in a scene with Toheeb Jimoh's Prince Hal and Henry Percy, played by Samuel Edward-Cook.

Shocked audience

“Sir Ian seemed to trip as he moved downstage to take a more active part in the scene,” audience member Paul Critchley told the PA news agency, saying it was a shock.

“He picked up momentum as he moved downstage which resulted in him falling off the stage directly in front of the audience.”

Staff and two doctors in the audience helped the actor, the theatre said in a statement.

The theatre was evacuated and the performance was canceled.

McKellen played Magneto in the “X-Men” films and is one of Britain's most acclaimed Shakespearean actors, with roles including Richard III, Macbeth and King Lear.

He has won a Tony Award — for “Amadeus” — several Olivier Awards, and has been nominated for two Academy Awards, five Emmys and several BAFTA awards.