AceShowbiz - Actor Billy Crudup has been ordered to stay silent in between performances of his one-man show "Harry Clarke" to preserve his vocals. The "Watchmen" star recently returned to the Off Broadway stage for the David Cale drama, about a shy Midwestern man who leads a double life as the titular cocky Londoner.

The challenging solo show requires Billy to portray a total of 19 different characters in the space of 75 minutes, and to ensure he has the vocal stamina to last throughout the production, he has to avoid talking during his down time.

"I have been mostly on vocal rest, 'cause I'm doing a play right now where I do most of the talking... and by the end of it, I can't say anything; my voice is absolutely spent," he told morning show "Live with Kelly and Ryan". "I'm doing the best that I can right now (for this interview)."

Billy admits working on such an intense play consumes much of his time, because there is so much dialogue to memorize. "You lose everything else in your life...," he joked. "It does feel like my version of a daredevil act, because I have to psyche myself up for it every night," he recently shared with Playbill.com. "I don't think I've ever had an experience as intense."

But he's having a great time, adding, "It's in a small theatre, and it's a great New York experience. You simplify what it is to be in the theatre... (and) you don't have to worry about the other actors remembering their lines!"