"We're always there for each other," Tisdale, 25, told PEOPLE of her former castmates Wednesday at the DVD release of her HSM spin-off Sharpay's Fabulous Adventure. "I love being with them. They're so supportive. It's just like a bond. I can't explain it, but they're like a family I've grown up with."
Tisdale says the trio always pick up right where they left off. "We're growing up and we're working on different projects, but we're all super supportive of each other," she says. "They're like my brothers and sisters."
The bond between the three stars, forged beginning with the first HSM in 2006, was evident at Tisdale's Soho House launch party in West Hollywood, where both Efron and Hudgens were all smiles as they came out to support their pal.
Hudgens, 22, rocking a shorter, pinned-up 'do, told PEOPLE she was "feeling great" fresh off a trip to France, where she and her mom "enjoyed eating crepes."
She and Efron, 23, took their turns posing with Tisdale on the carpet, before the three were led to a private area in the back of the venue, where they celebrated with Tisdale's family and other former HSM stars.