Everyday "High School Musical" fans have waited for Disney to announce once again that "we're all in this together" for a fourth installment of the popular franchise that launched the careers of Zac Efron and Vanessa Hudgens. On Tuesday, it finally happened when Disney Channel launched a nationwide casting call for "High School Musical 4."

Casting on the new TV movie begins more than a decade after the original "High School Musical" premiered. The story will pit the East High Wildcats against their crosstown rivals, the West High Knights.

"'High School Musical' is part of Disney Channel's DNA. It embodies all that we stand for. As a way of continuing to embrace that heritage, we're excited to announce 'the start of something new," Gary Marsh, president and chief creative officer, Disney Channels Worldwide, said in a statement. "As we launch a search for a new class of East High Wildcats to star in fourth installment of the 'High School Musical' franchise."

"Teen Beach Movie" director Jeffrey Hornaday will help the latest "HSM" movie as well as handle the choreography. Peter Barsocchini, writer of the first three "High School Musical" movies, will co-write the fourth film with Dan Berendsen, who also wrote "Hannah Montana: The Movie" and "Teen Beach 2."

The original TV movie premiered on Jan. 20, 2006 to 7.7 million total viewers in the U.S. It delivered the first ever TV movie soundtrack to reach No. 1 on the Billboard 200 and also became the No. 1 album of 2006.

The "High School Musical" cast reunited in January to celebrate the movie's 10-year anniversary. Hudgens and her co-stars Ashley Tisdale, Corbin Bleu, Lucas Grabeel and Monique Coleman met in a gym recreated to look like East High. Efron sent in a pre-taped message for fans.

None of the original cast has been confirmed to reprise their roles. The best bet would be Tisdale, whose character Sharpay Evans was going to assist Ms. Darbus (Alyson Reed) with the East High drama club while she attended college nearby. Reed, who remains active recently guest starring on TNT's "Major Crimes" and HBO's "Silicon Valley," could also return along with Bart Johnson, possibly returning as East High's basketball coach.

Disney has not announced a premiere date for "High School Musical 4."