"H.S. Musical": Pop Culture Phenomenon

If you ever stumble across thousands of screaming tweens, it is a safe bet there are "High School Musical" stars close by.

A pop culture phenomenon, "High School Musical" has become one of the biggest sensations of the last few years as versions 1 and 2 sold more than 15 million DVDs and 13 million sound tracks.

Now, with the release of "High School Musical 3: Senior Year," the stars will be saying their goodbyes and heading off in different directions.

Early Show correspondent Hattie Kauffman went to the "High School Musical 3: Senior Year," premiere in L.A. and chatted with the dancing and singing sweethearts.

"People before us had 'Grease' and 'West Side Story,' there have been a lot of great musicals, but this is something unique," said "High School Musical" heartthrob Zac Efron.

"High School Musical" is considered the biggest screen franchise in the world.

Director Kenny Ortega credits the chemistry between Vanessa Hudgens and Efron, something he saw when casting for the first "High School Musical."

"We sort of sent all the actors out of the room and we looked at each other and said we would be crazy if we didn't select them," said Ortega.

Unlike most other movies, "High School Musical" is so clean that there is hardly a kiss.

"As a mom, you can leave the room, the kids can watch, you don't worry," said actress Holly Robinson Peete.

"It's good, clean, family fun. That's why you sit down and watch it with your kids and you enjoy it," said "Beverly Hills 90210" star, Lori Loughlin, who had sarcastically compared it to the racy "90210."

Although the music gets fans pumped up again, the story line is a sad one for "High School Musical" fans. The stars are graduating from high school, which means no more singing in the bleachers or dancing at proms.

"Just way too emotional. Just horrible. I could not stop crying," said Hudgens.

"We were crying hysterically, so it's definitely something that we'll always remember for the rest of our lives," said star Ashley Tisdale.

"High School Musical 3" opens on Oct. 24.