The show must go on, but not if the star -- in this case Christian Slater (search-- has chicken pox.

Producers had to cancel the opening night of "One Flew Over the Cuckoo's Nest, (search)" which was due to open in Edinburgh Friday and run for three weeks in conjunction with the city's annual arts festival.

"We so hoped we would be able to make the first performance but poor Christian's chicken pox has simply been too virulent," said producer Nica Burns.

"In order to safeguard the rest of the run we are having to take the doctor's advice to let Christian recover for one more day," she said Tuesday. "R.P. McMurphy is an enormous part requiring great energy."

The play is to run at Edinburgh's Assembly Rooms before moving to London's West End (searchin September.

The producers said those holding tickets for Friday can exchange them for another night or get a refund. They said the rest of the run would go ahead as planned.

Jack Nicholson (searchwon an Oscar for his role as McMurphy in the 1975 movie adaptation of Ken Kesey's novel, set in an Oregon mental hospital.