Diddy and a host of celebs got their party on well before Sunday's big game.

There's a reason it's called Super Bowl weekend. Mobs of celebs flocked to Scottsdale, AZ, -- the site of this year's big game -- as early as Friday to party at the Fairmont Scottsdale Princess resort, the Associated Press reports.

Stars in attendance according to the AP included SEAN "DIDDY" COMBS, LARRY DAVID, TOM PETTY, NFL-great JOHN ELWAY, "Entourage" stars ADRIAN GRENIER and KEVIN DILLON, reality starlets KIM KARDASHIAN and HEIDI MONTAG, JERRY O'CONNELL and ROB SCHNEIDER.

As ET previously reported, Petty, ALICIA KEYS, JORDIN SPARKS and "American Idol"'s PAULA ABDUL are set to provide the musical score to this Sunday's Super Bowl XLII.