Katharine McPhee has joked about going nude in her upcoming show, Smash.

The American Idol runner up stars in the anticipated new musical series which is being touted as Glee for grown-ups.

And the 27-year-old actress teased fans in the March issue of GQ magazine that there will be a lot more adult content in her show.

"What if I tell your readers that in episode five I take off all my clothes," she laughed. "I mean no. But can't we just say that?"

Katharine plays Karen Cartwright who is a young starlet from Iowa who moves to New York City to break into showbiz.

She is pitted against experienced Broadway veteran Ivy Lynn, played by Megan Hilty, to try and win the role of Marilyn Monroe in a stage show.

Although there are similarities with hit show Glee, Katharine says she understands why high-school show does not have as wide an appeal as she hopes Smash will.

"I can understand why guys wouldn't be into Glee," she stated. "You know, that's a pretty heavy musical show. That show does like, six songs in an episode. We'll do, at most, three."

Smash is executive produced by Steven Spielberg and also stars Will & Grace star Debra Messing and British actor Jack Davenport.