Katy, Britney and Leighton Meester join forces with Selena

Katy Perry and Britney Spears appear on a CD together but it's not the latest Now compilation.

Rather, the pop singers have written songs on Selena Gomez and the Scene's new album, When the Sun Goes Down.

"I did have a lot of artists that I was very lucky enough to have songs written by and it's a good, uplifting album," Gomez said of her third CD. "It's really fun and very dance-y and I hope people like it."

Spears co-wrote the dance song Whiplash, while Perry co-penned That's More Like It. Singer Priscilla Renea co-penned three songs on Gomez's album, including the lead single and Top 40 hit Who Says. And the disc has a writing credit and guest appearance from British singer Pixie Lott.

"I think it's a powerful CD," Gomez said in a recent interview.

The 18-year-old's first two albums have reached gold status. The new record — which has three songs co-penned by Gomez — is out next week.

Days after her disc's release, Gomez will get another girl power boost with the release of her new movie, Monte Carlo, which also stars Leighton Meester of Gossip Girl and was co-produced by Nicole Kidman.

The singer-actress, who is dating teen pop star Justin Bieber, says she enjoys having friends "in the business" and others who are not.

"Personally for me, I feel like it's good to have a balance of both," she said. "I have people in my life that are in the business and then I have friends who aren't in the business and family, so it's nice to kind of keep that.

'Normal things'

"You want people that obviously understand what you're going through and then you also want people that's like, 'Let's not talk about [movie] sets or press or any of that, let's just talk about normal things.'"

Yet the entertainer, whose Wizards of Waverly Place is ending its fourth and final season on Disney, says she's noticed that her life — and the people around her — are changing.

"Your life definitely changes a little bit and you kind of think people's motives change toward you," she said. "Just got to be careful — that's all."