Slater caught chickenpox from cast member Felix Dexter

Slater, 34, was taken ill on Friday while rehearsing One Flew Over the Cuckoo's Nest in London.

However, its producers remain hopeful he will recover in time to appear in the first performance on 6 August.

The show had earlier lost its director when Guy Masterson quit the production, blaming stress and family illnesses.

"Felix Dexter, a member of the cast, was struck down with chickenpox in the second week of rehearsal," said producer Nica Burns on Saturday.

Christian and company are in fantastic spirits Nica Burns

"We had hoped that the rest of the cast had escaped it, but yesterday Christian was taken ill and it is confirmed today that he has it."

"Despite this, Christian and company are in fantastic spirits having had an inspiring week of rehearsals," Burns continued.

"Whilst Christian is recovering the cast continue to rehearse and will be arriving in Edinburgh next week."

Slater, star of True Romance and Robin Hood: Prince of Thieves, plays Randle P McMurphy in the production, a role made famous by Jack Nicholson in the Oscar-winning 1975 film.

Slater's co-stars include Frances Barber and Mackenzie Crook

The play, written by Dale Wasserman, is adapted from the book by the late Ken Kesey.

Actress Frances Barber and The Office star Mackenzie Crook also appear in the show, which transfers to the Gielgud Theatre in London following its three-week run at the Assembly Rooms in Edinburgh.

One Flew Over the Cuckoo's Nest has been the subject of intense scrutiny since Masterson left the production on 23 July. The play is now being co-directed by Tamara Harvey and playwright Terry Johnson.

In an interview with The Guardian published earlier this month, Barber - who plays the sinister Nurse Ratched - said she had "never been involved in any rehearsal process quite like this".