While we don't yet know which members of the original "High School Musical" cast will be returning, we do know that Sofia Wylie, Julia Lester, and Frankie Rodriguez are coming back for the fourth season of "HSMTMTS," as well as Joshua Bassett (although Olivia Rodrigo will not be returning for her role as Nini). Previously, KayCee Stroh, Lucas Grabeel and Corbin Bleu have all guest-starred on the show, but seeing who else joins the cast will be one of the most exciting parts of this season. Given that both Vanessa Hudgens and Zac Efron posted pictures of East High over the summer, fans are definitely holding out hope to see the stars reprise their iconic roles as Gabriella and Troy.