Katy Perry celebrates release of ‘Part of Me’ movie with Hollywood performance – and Justin Bieber and Rob Pattinson!

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Katy Perry was living out a teenage dream on Tuesday night. After performing for a huge crowd in Hollywood, following the premiere of her new movie "Part of Me," she partied the night away with none other than Justin Bieber, Selena Gomez, and Robert Pattinson. But before that, the pop star put on quite a show for her adoring fans who took over Hollywood Boulevard. Wearing a movie theater-inspired dress featuring red-and-white stripes, huge popcorn pieces, and film reels, Perry performed a bunch of her biggest hits, including "I Kissed a Girl" and her new song "Wide Awake."

After the film ended, Perry, 27, started her night at the Chateau Marmont with her very random group of famous friends. From there, they all piled into a party bus — or in Bieber's case, he jumped head first into it — and headed over to David Arquette's new club, Bootsy Bellows, his mother's burlesque name. "They were all hanging out in the VIP room," a source tells E! Online. "They were all just talking and having a good time." (Apparently, the club's 21-and-over policy doesn't go into effect until it officially opens its doors this Friday, so 18-year-old Bieber and 19-year-old Gomez were allowed inside.)

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Pattinson, 26, was without his girlfriend Kristen Stewart, but he still had a lady to keep him company. Perry's good friend Shannon Woodward, who stars on "Raising Hope," was spotted by his side throughout the night — while the "Twilight" actress was thousands of miles away in Paris shooting a Balenciaga perfume campaign.

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