Young children, teenagers and their parents packed out the Greater Union cinemas and lined George Street in the CBD for the premiere of "High School Musical 3: Senior Year."

Some fans had been there since 8 a.m. to get a front row position in the hope of nabbing an autograph, a photo or just to catch a glimpse of the Disney stars.

Cheerleaders warmed up the already excited crowd, and when the Hollywood stars arrived the screams turned from loud to ear-splitting.

"It's very overwhelming," said Hudgens, dressed in a cream BG Max Azria gown. "It's incredible though, the fans are so amazing."

Hudgens received gifts of flowers from admirers, as well as a large box of Tim Tam biscuits. "They're my favorite," she said. "It's so sweet, it's the little things that count."

High School Musical series follows the story of basketball captain Troy (Efron) and brainy but shy Gabriella (Hudgens) who discover they have a secret passion for singing and try out for the student musical.

In the third and final film, the students hit senior year, having to make tough decisions about their future and putting a question mark over Troy and Gabriella's relationship.

Efron, who is also Hudgens' boyfriend off screen, inspired some of the loudest squeals from the mostly female crowd.

He said it was a bittersweet experience to be leaving High School Musical behind. "I love being a part of High School Musical, I wish I could do it forever but everyone's got to grow up," he said.

Efron is set to star in a remake of the 1984 dance film Footloose next but said he's also keen try other movie genres. "I'd love to try it all," he said. "I'll see where the wind takes me."

They will walk the red carpet again in Melbourne today.