Britney Spears and Justin Timberlake were under the same roof at the House of Blues in Los Angeles.

Britney Spears and Justin Timberlake party at the House of Blues

Britney was backstage having a great time hanging out with a friend named Marianne, an eyewitness tells Star. She hung for a bit, then left through a side entrance at 10:37 pm, covering her face.

Justin and gal pal Jessica Biel were spotted in the VIP Lounge, bopping to the music and enjoying cocktails. "He had his arm around Jessica the entire time and they were constantly kissing each other," says an onlooker. "They looked like they were having a blast. They are obviously in love."

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