NEW YORK —  Madonna wasn't burning up with desire to see Justin Timberlake's butt when she gave him a B-12 shot in the behind, as she admitted to doing earlier this month when she was inducted into the Rock and Roll Hall of Fame.

"First of all, I've seen enough butt ... The reason I gave him a B-12 [shot] is because we only had a certain amount of days in the studio and I didn't want him to use that as a lame-ass excuse not to come to work. OK? It's got nothing to do with butt. I promise you. Listen, I don't need to give him a shot to see his butt. Duh," she tells New York's Z100-FM in an interview scheduled to air Friday.

She also says she doesn't think she would have gotten very far on "American Idol."

"I went to a lot of auditions for musical theater and conventional mainstream things — and I always got cut immediately. So I'm pretty sure the same thing would happen to me."

As for her still-popular hit songs, "Holiday" and "Like a Virgin," she says she's "not sure she can sing them ever again."

"I just can't — unless somebody paid me like $30 million or something. [Like if] some Russian guy wants me to come to the wedding he's going to have to a 17-year-old, you know it."

And she's still rooting for her former pal Britney Spears.

"I actually love Britney Spears' new album ... I usually work out to her record. I do a combination of Pilates and dance aerobics," she says.

Madonna's new album, "Hard Candy," comes out on April 29.

Click here to read more and to hear the interview at People.com