JoJo, Emma Roberts and Sara Paxton at Aquamarine premiere

It's not every day that Emma Roberts is asked to tone down her skills, but that's what she did for her latest film, "Aquamarine." Directed by Elizabeth Adler, the comedy stars Roberts as Claire, a girl who's afraid of swimming after she loses her parents in a boating accident. She has to face her fears, however, when she and her best friend Hailey (Joanna "JoJo" Levesque) brave a storm-tossed sea to help their new pal, the mermaid Aquamarine (Sara Paxton). "I love the water. It was so difficult because we were in that tank and it was so much fun," she says. "I would always be swimming around, having a great time, and the director, Liz, would come to me and say 'You look like you're having way too much fun over there. You need to look like you're struggling out there.' So I had to slow down and do the doggy paddle really slow." Roberts, 15, was encouraged to show off another talent for the film though. After performing songs on her hit Nickelodeon show "Unfabulous" and releasing the album "Emma Roberts: Unfabulous and More," the tween star was asked to cover Weezer's "Island in the Sun" for the "Aquamarine" soundtrack. "We had to shoot the Last Splash dance scene, and that was the song that was playing. So we probably heard that song about a hundred times, and I got back to LA and they asked if I wanted to sing that song," Roberts explains. "I was like 'Yeah, I guess.' I had heard it a trillion times so I know it by heart already. I like Weezer so it was cool." Roberts is in good company. Both of her co-stars also balance music with their acting careers. JoJo is the youngest singer to debut at No. 1 on the Billboard Hot 100 with her single "Leave (Get Out)," and Paxton, who also contributed to the soundtrack, is working on her debut album "The Ups and Downs." "We're all fans of each other. JoJo had just finished her music video, so they sent it to her and we all watched it together," says Roberts. "All of us just kind of bonded on a normal teenage girl level and never really talked about [singing together]." [Zap2it]