Forget the fact that she's a former Disney star who's releasing a music album the same week as a major motion picture -- those are certainly reasons to be exhausted.

But it seems that American actress and pop singer Selena Gomez had an additional challenge when she accepted the role of Grace in 'Monte Carlo,' a romantic comedy directed by Tom Bezucha, due in theaters July 1. In the film, loosely based on Jules Bass's 2001 novel 'Headhunters,' she not only had all her lines to memorize, but had to deliver them in a convincing British accent.

"I had two weeks of training before the film, and I was so nervous," admits Gomez, 18, whose character pretends she's an heiress named Cordelia.

"We had to pick the right dialect for the character, so we chose proper [English]," she continued. "We had a find a lower register for me, and [I learned] all these techniques, like you have to pretend there's an oval shape around the inside of your mouth. It was a little hard, but my coach was really helpful, so she made me feel confident. She just told me to own it, so hopefully people buy it."

The original book is about four vacationing, middle-aged New Jersey friends looking for potential husbands in Monte Carlo. They pose as wealthy women while they troll casinos on the hunt for Mr. Right. But after a false start adapting the screenplay, Fox decided to skew the demographic younger and modify the story line.

"It's about three girls who travel to Europe. They want to have an amazing vacation and just get away from everything," Gomez says of the movie's plotline. Her castmates are Katie Cassidy (who plays Emma) and Leighton Meester (Meg).

"It ends up being a total disaster," continues Gomez. "I play a British heiress as well, who we switch lives with and I pretend to be her and get all this free stuff. And within that, we fall in love with different characters. It's a whole big thing that's really fun."

Gomez, who has a parallel career as a pop singer, has been in the entertainment business since age 7, when she landed a part on the kids show 'Barney & Friends' for two seasons. She got her first feature film role at age 11 in the sci-fi adventure 'Spy Kids 3-D: Game Over.' She was also the star of the Disney Channel series 'Wizards of Waverly Place' from 2007 to 2010, during which time she launched a music career.

Her third album with her band The Scene, 'When the Sun Goes Down,' comes out June 28 and she'll back it up with a tour.

The acting role in 'Monte Carlo' did make her "nervous," she says, "but that was such a good challenge for me. It's so different and that's what I love about acting -- finding new things and reinventing myself."

'Monte Carlo' hits theaters July 1.