Clay Aiken, who joins the cast of "Monty Python's Spamalot" this week, says its humor was initially lost on him.

"The first time I saw it I thought it was the stupidest thing I'd ever seen in my entire life," the "American Idol" runner-up told Newsweek. "My tour drummer is the 'Spamalot' drummer, and (he) said you've got to see it again."

Aiken plays one of the leads, Sir Robin, in the Tony Award-winning musical in a stint from Friday through May 4.

The show is based on the film "Monty Python and the Holy Grail," which came out in 1975, a little before the 29-year-old singer's time.