What do vampires + devious gossips + teen superheroes + high school musical hotties combine to make? One seriously hot PSA, that's what.

HIV/Aids has been a top cause for celebs worldwide for some time now, but this new celeb PSA calling on young people to help stop preventable diseases like AIDS, malaria, and tuberculosis is filled with the hottest celebs of this year. Check it out to see the stars of Gossip Girl, Heroes, and of course, Twilight speak for themselves (and P.S.: we could get used to Ed Westwick's accent...)