One of Helen Mirren's pivotal co-stars in London's Royal National Theater's staging of Shakespeare's "Antony and Cleopatra" is refusing to work with her.

It seems Cedric the snake has slunk off rather than participate in the climactic scene in which Cleopatra, played by Mirren, commits suicide by pressing a snake to her bosom to administer a fatal bite.The California king snake has not been seen since he escaped from his box in the theater's offices four days ago, a theater spokeswoman said.

But the show will go on - with another snake that has played the Egyptian asp in rehearsals.

"Antony and Cleopatra," which also stars Alan Rickman, opens Oct. 20.