It was a wild weekend in Las Vegas -- with stars like Vanessa Hudgens, Britney Spears, Fergie, the kids from "Twilight," a "Jersey Shore" star and more all partying in Sin City!

A couple pop stars kicked off the weekend Friday night, when both Britney Spears and Lady Gaga gave concerts in LV. Britney performed a three-song set at the Palms with DJ Pauly D, while Gaga did a full concert for fans the MGM.

Two birthday girls also got their party on Friday, with Fergie celebrating her 36th in a skin-tight dress with a bash at The Bellagio's Bank and Disney/"Social Network" star Brenda Song feasting on a b-day cake at TAO Beach at The Venetian Las Vegas.

Ronnie from "Jersey Shore" also went clubbing Friday night, celebrating Spring Break at LAX at Luxor, where he was spotted dancing on his booth with a group of ladies.

On Saturday night, "Sucker Punch" star Vanessa Hudgens celebrated the release of her movie with a party at PURE Nightclub at Caesar's Palace -- where she was seen dancing with her mom and singing along to songs like "Hold It Against Me" and "Firework." She also was spotted having dinner with rumored new boyfriend Josh Hutcherson.

The Sugar Factory American Brasserie hosted a number of celebs this weekend too -- including Flo Rida, Asher Roth, Stephen Dorff and "Twilight" stars Tinsel Korey, Kiowa Gordon and Bronson Pelletier.

Check out the gallery above to see all the hot Vegas sightings!

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