Sir Ian McKellen fears being caught short on stage in new play

Sir Ian McKellen and Sir Patrick Stewart play ageing writers who spend the night drinking

Sir Ian McKellen has revealed he tried to alter Harold Pinter's play No Man's Land to insert a crucial twist - a toilet break for his character.

Sir Ian and Sir Patrick Stewart play drinking partners in a new production.

Sir Ian told BBC Radio 4 Front Row: "My character never leaves the stage for two hours and he drinks an awful lot - and I tell you when you drink at this rate, you simply have to go and pee.

"But he's not put that in the play. We tried to put it in the play."

The actor added: "I'd say that was as close to an error as Harold Pinter ever got."

Despite his comments, Sir Ian will get a reprieve during the interval.

The production opens in Sheffield on Wednesday and will travel to Newcastle, Brighton and Cardiff before embarking on a three-month run at London's Wyndham's Theatre.

Getting drunk without alcohol

Sir Ian and Sir Patrick play ageing writers who spend the night drinking. The play was first performed in 1975, starring John Gielgud and Ralph Richardson.

While Sir Ian is on stage for the duration, Sir Patrick's character does have the luxury of a break.

"He goes off for half an hour's sleep and comes back sober and rested," Sir Patrick said.

The actors consume only non-alcoholic drinks on stage - which Sir Ian revealed can have an effect on the brain as well as the bladder.

"I don't know how it happens," he said. "We've all experienced it at rehearsals.

"There we are sipping water - pretend champagne, pretend gins, pretend whiskies, pretend vodkas - water, water, water, water.

"And by the end we were sort of slurring our words. You can get drunk without drinking alcohol, it turns out."

'New audience for live theatre'

The play sees a reunion for the two stars of the X-Men movies and both actors believe fans of their other major screen franchises will also visit the theatre.

Sir Ian played Gandalf in the Lord of the Rings and Hobbit movies, while Sir Patrick was Captain Jean-Luc Picard in Star Trek: The Next Generation.

Sir Patrick said: "It gives both of us a lot of satisfaction that, because of the very popular and successful franchises we've been in, we are creating a new audience for live theatre, and especially a young audience.

"Teenagers who have been watching The Hobbit and The Lord of the Rings - they want to see Gandalf, they want to see Jean Luc Picard and Charles Xavier and Magneto.

"That doesn't matter to us. We don't care why they come."

Front Row is on BBC Radio 4 on 3 August at 19:15 BST - the episode will later be available on the Front Row website.