Gerard Butler to Demi: 'You Shook Me All Night Long'

7/24/2010 4:05 AM PDT BY TMZ STAFF
Patrons of a karaoke bar in Michigan got the unexpected surprise performance of a lifetime when Gerard Butler, Demi Moore and Michelle Monaghan took time out from shooting their latest films to belt out ACDC's "You Shook Me All Night Long" the other night.

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While it's obvious everyone at Rockstarz Karaoke Bar & Grill had a blast, it's also safe to say Gerard and crew will most likely hold on to their day jobs.

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