Stamos Goes by 'Stay-moist' on Broadway?!

Sexy John Stamos is telling "Extra" all about getting in shape for his Broadway show "Bye Bye Birdie" -- and he even dishes his backstage nickname!

John Stamos

Stamos is looking more fit than ever and he tells "Extra" he intensified his workout routine. "I've just been doing a lot of cardio," he says. Stamos adds, "But I sweat so much." The 46-year-old hunk says his castmates gifted him with a sweatband for his birthday and his new nickname is "John Stay-moist."

The handsome Stay-moist, er, Stamos will star in the Broadway revival of "Bye Bye Birdie" this fall. "I love doing theater. That's why I try to come back every few years," he explains. Stamos has also appeared on Broadway in "Cabaret" and "Nine."

Fans love Uncle Jesse and his Elvis Presley obsession and John admits he misses the good times on "Full House." "I remember doing it and I was always telling Bob [Sagat] and Dave [Coulier] these are good ol' days. These are gonna be the days we remember."

"Bye Bye Birdie" runs from October 15, 2009 to January 10, 2010 at Henry Miller's Theatre in NYC.