"Femme Fatale," Britney Spears' seventh studio album, has a lead single that has topped the Hot 100, official album artwork, and a Mar. 15 release date that is slowly approaching. However, executive producer Lukasz "Dr. Luke" Gottwald, tells Rolling Stone that he and a band of A-list producers are still finalizing the follow-up to 2008's "Circus."

"It's not done," says Dr. Luke, who helmed lead single "Hold It Against Me" along with the album's co-executive producer Max Martin and Billboard (who is a producer). "We're in the middle of it right now. It's a little bit fluid right now. I can't even say at this stage what songs for sure are making it and what songs aren't. We're working with a lot of producers and overseeing it with her A&R and record label and management and trying to make something cohesive."

Britney Spears Reveals 'Femme Fatale' Album Title, Cover Art

The producer confirmed that he and Martin will be involved with several songs on "Fatale," while "Toxic" co-producer Bloodshy and "Circus" co-producer Benny Blanco will also contribute production to the record. Spears announced the title and revealed the album artwork to "Fatale" on Wednesday (Feb. 2), writing on Twitter, "This album is for you, my fans, who have always supported me and have stuck by me every step of the way! I love you all!"

Dr. Luke also revealed that "Hold It Against Me," Spears' latest single which slips to No. 8 on this week's Hot 100, might have never been hers to sing -- fellow female pop star Katy Perry was originally considered to handle the vocals.

"We might have played it for her, but it definitely wasn't a Katy Perry record," Dr. Luke says. "We had it for a while. I wanted to make sure it didn't sound like everything else I've done. I brought it into Billboard, and he just killed it. It can be hard in the verse, and the bridge is super, super hard, but the chorus is super-pop. You can play that chorus acoustically on a guitar and it's still going to sound great."