Zac Efron

High School Sweethearts Zac & Vanessa

By Lisa Ingrassia

UPDATED 11/10/2008 at 01:00 AM EST • Originally published 11/10/2008 at 01:00 AM EST

If Hollywood really is like high school, then Zac Efron and Vanessa Hudgens are the king and queen of the prom. Not only are the High School Musical 3 stars reigning over the box office—the film nabbed $42 million its first weekend—the duo also whipped up an awesome afterparty: They jetted to Hawaii for a romantic getaway and a pal's wedding.

Efron, 21, and Hudgens, 19, began dating in early HSM days in 2005, and their relationship strengthens by the year. Says HSM director Kenny Ortega: "The chemistry they have has grown big-time."