Here's the breakdown:
* High School Musical Cast: The core cast of High School Musical includes Zac Efron, Vanessa Hudgens, Ashley Tisdale, Corbin Bleu, Lucas Grabeel, and Monique Coleman.
* Maddie Ziegler: Maddie Ziegler is a dancer and actress known for her work on "Dance Moms" and in Sia's music videos.
There's no evidence to suggest that the High School Musical cast and Maddie Ziegler are close friends. They come from different entertainment backgrounds and have separate circles of friends.
While it's possible they've met through industry events, there's no known connection or public statement indicating a close friendship.