The comics performing in the West End smash One Flew Over The Cuckoo's Nest are staging a free performance next week.

This extra show will give the understudies to take on the lead roles – which means Christian Slater and Frances Barber will not be appearing.

But stand-up Phil Nichol, above, will be playing Randall P McMurphy, the rebellious mental patient made famous by Jack Nicholson, and comedy actress Katherine Jakeways, right, will be the uptight Nurse Ratched.

Jakeways said: “As Christian Slater and Frances Barber have both, luckily,  had the constitutions of oxen since August, neither  of us have played the roles, other than in rehearsals.

“So we're doing a special performance, with me and Phil playing McMurphy and

Ratched, the four other understudies playing parts, and the rest of the cast playing their normal roles.

“It's a good opportunity to see the show.  The only difference is going to be that there'll be no movie stars in it.

The supporting cast includes comics Owen O'Neill, Ian Coppinger, Dave Johns, Lucy Porter, Lizzie Roper, Stephen K Amos and Felix Dexter.

The show takes place next Tuesday at 3pm. To see it, just turn up at the Gielgud Theatre box office on Shaftesbury Avenue in time for curtain-up.