The 'High School Musical' heartthrob would love a role in the movie because he was such a fan of the first film, which was a worldwide box office smash.
Zac Efron said: "I haven't got that call yet to join them but that would be amazing. I think that they're amazing and I love the cast that they've got going on."
One of the comedy's stars, Ed Helms thinks the 22-year-old actor would be a great addition to the cast.
He said: "I love that guy. He's actually really funny."
'The Hangover' tells the story of four men who go on a bachelor party in Las Vegas and wake up the next morning with no memory of what happened the night before and have lost the groom-to-be.
Justin Bartha – who plays the lost groom Doug Billings – would also like Zac to appear in the sequel, along with 'Twilight' stars Robert Pattinson and Taylor Lautner, because they would attract different filmgoers.
He told US TV show 'Access Hollywood: "If it gets people in the seats, yes, Zac Efron and the 'Twilight' guy. All the 'Twilight' guys - every one of them with their shirts off, and Will Smith."