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Awkward alert!

Wilmer Valderrama hosted a Christmas party/dinner at RivaBella in West Hollywood last night, and he invited former flame Demi Lovato!

She raced off in her white Mercedes after the party -- either she was really tired after the X Factor finale, or she just not in the mood to be seen after running into her ex. OR ... are the two secretly shacking up again and she was trying to sneak out?

Despite the fact Wilmer's 12 years her senior, the two have reportedly rekindled their romance a few times over the years, most notably after she got out of rehab in 2011 and in October of 2013 when the duo were spotted holding hands at Knottā€™s Berry Farm Halloween Haunt.

Demi, who just announced that she's leaving the X Factor, did seem to be in good spirits while posing for photos with Kelly Rowland prior to the party:

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