Joe Jonas & Lauren Conrad: New Year's Eve at Bellagio!

Lauren Conrad puts on her party hat as she celebrates the new year with gal pal Stephanie Pratt at Hyde Bellagio in Las Vegas on Saturday night (December 31).

The 25-year-old author/designer partied it up at the new nightclub inside the Bellagio Casino and Resort with a full crowd — which included Sofia Vergara, Wilmer Valderrama, and Joe Jonas.

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Lauren posted well wishes for the new year on her official site, “Happy New Year everyone! Wishing you the best of luck in 2012. Cheers to good health, success and love in the New Year!”