Ashley Tisdale Ashley Tisdale

Ashley Tisdale may have moved on from her High School Musical days, but wanted to return for Sharpay's Fabulous Adventure to give her famous character a proper send-off.

"The fact that I'm here today is because of the fans of High School Musical and the fans of that character, and I felt like I owed it to them to have a really good ending for her," she tells

Sharpay was quite the mean girl in the first two films of the Disney franchise. In the final movie, after getting rejected from Juilliard, she decides to remain in New Mexico and help her teacher, Ms. Darbus, run the drama department.

Tisdale wasn't so satisfied with Sharpay's outcome. "In High School Musical 3, everyone else was going off to these amazing colleges and I stayed pretty much to get an apartment with Ms. Darbus. I'm like, 'That's it?' So I was like really excited when I read this script. This was such a great ending to this character that has given me so much," she says.

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In Sharpay's Fabulous Adventure, the recent high school graduate sets her sights on New York City to fulfill her Broadway dreams. Between a huge audition mix-up and finding a scary shoebox of an apartment, the always pampered girly-girl realizes that life ain't always so easy. "She's always gotten everything she's always wanted, she's very spoiled, and then she's faced with challenges in New York City. We see her evolve throughout the entire movie to where she finally grows up," Tisdale says.

One of those "a-ha" moments is Tisdale's favorite scene in the film, in which she performs a number called "New York's Best Kept Secret." "Sharpay is known for being on stage with props and a humungous show, and this is the first time she's not only the most vulnerable in her life, but she's vulnerable on stage. You've never seen Sharpay like this before," she says.

Tisdale says that not only will fans of High School Musical series love her latest spin-off, but that there's a surprise for those who tune in. "It's the first time we're seeing Sharpay and her twin brother Ryan [Lucas Grabeel] back on screen, and it's only on the Disney Channel — It wasn't on the DVD. They always wanted there to be a secret cameo and it's a cute little scene at the end of the movie," she says.

Although this may be the last we'll see of Sharpay, Tisdale has some ideas as to where the character might end up a few years from now. "I think probably Sharpay would want to be like Lady Gaga, going into a pop career after her Broadway career," she says. "She's going for it big time."

Sharpay's Fabulous Adventure airs Sunday at 8/7c on Disney.

Watch a clip from the movie.