Miley Cyrus' Mystery Man Identified!

USMagazine, Friday, March 8, 2013, 12:20pm (PST)

Miley's wild night out -- without Liam Hemsworth. The "Can't Be Tamed" singer turned up at a house party in North Hollywood on Thursday, March 7 with an unidentified, dark-haired male companion. And, for the second night in a row, the 20-year-old former Hannah Montana star opted not to wear the 3.5 carat diamond engagement ring from fiance Hemsworth, 23.

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After spending some time at the bash, Cyrus and her mystery man departed together in her car, with Cyrus' friend taking the wheel. (UPDATE: A source confirms to Us Weekly that Cyrus' mystery man is Hemsworth's friend Paul Khoury.)

The LOL actress' first ring-less appearance was on Wednesday, as she headed to a recording studio elsewhere in L.A. Hours earlier, she took to Twitter to deny that her 10-month engagement to Last Song costar Hemsworth was off. "I didn't call off my wedding," Cyrus tweeted. (See more photos Miley's night out.)

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Still, multiple insiders tell the new Us Weekly that there's been major trouble brewing for Cyrus and Hemsworth as they battle over their dueling careers, Cyrus' shocking image makeover and other issues. "He's not happy," one pal says of the Australian actor. "She says she's over it."

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Get more details on the couple's crumbling union -- and Hemsworth's fling with one A-list actress -- in the new issue of Us Weekly, on stands now!

This article originally appeared on Usmagazine.com: Miley Cyrus' Mystery Man Identified!