The 23-year-old actor wrote a super sweet message for Bella, 17, on his Instagram account following the big night out.
“So proud of you @bellathorne. Apart from being naturally gifted, beyond beautiful and very talented, it proves hard work pays off :) such a good performance. You deserve everything and more… And ps. You just made the #scream franchise that much better,” Gregg said.
Other members from the cast that stepped out at the premiere included Willa Fitzgerald, Bex Taylor-Klaus, Carlson Young, John Karna, Connor Weil, Bobby Campo, Amadeus Serafini, Tom Maden, and Brianne Tju.
FYI: Bella is wearing a Mugler dress, Stuart Weitzman shoes, a Salvatore Ferragamo clutch, and XIV Karats jewelry.