What happens when a rising British star gets the call to enter the halls of East High? A good old-fashioned freak-out.

"I ran around the house screaming," Jemma McKenzie-Brown said, thinking back to the day she was asked to a final audition for [article id="1579643"]"High School Musical 3: Senior Year."[/article] "My grandma was like, 'What's wrong?' I was like, 'Nothing, nothing. I'm really excited!' "

Not exactly the reaction you might expect from an experienced star of British television and radio. But the call came near the end of months of auditions for "HSM3" and eventually earned the 14-year-old a spot as the new kid at the "High School Musical" table. She plays Tiara Goal, a transfer student from England who becomes Sharpay's personal assistant/ "mini-me" in the upcoming flick.

And yes, she admits to being a bit nervous when she first rubbed elbows with East High's major stars, but she said the vets did their best to make her and the rest of the new kids feel welcome.

"They incorporated us into everything they did," McKenzie-Brown said. "If they were all hanging out in someone's room, they'd ring us or text us, so it was really cool."

McKenzie-Brown's work on the BBC drama "Mrs. Pritchard" has already gotten her noticed on the street (well, once anyway), and the actress is doing her best to prepare for a whole new level of fame once "HSM3" hits.

"It's just too huge. Everything is really surreal, and it hasn't sunk in yet," she said. "You have to take a step back and just think of what is actually going on. It's crazy. It's not something you ever imagine happening to you, so luckily it has. I'm really fortunate."

Check out everything we've got on "High School Musical 3: Senior Year."

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