Gerard Butler, Demi Moore and Michelle Monaghan sing karaoke

42490, DETROIT, MICHIGAN - Monday July 12 2010. Gerard Butler sporting a rather fine mullet as he shoots scenes for the forthcoming thriller Machine Gun Preacher in Michigan. The fact-based drama sees the Scotish hunk as Sam Childers, an outlaw who renounces his bad ways and becomes a warrior for the desperate and helpless children in a war-torm African country. Photograph: Smith, Steinberg,  PacificCoastNews.comGerard Butler, Demi Moore and Michelle Monaghan took time out from filming for a spot of karaoke.

The A-listers went to Rockstarz Karaoke Bar & Grill in Michigan to rock out.

Singing along to ACDC’s You Shook Me All Night Long, the crew looked like they were having a blast.

But, were their singing voices up to much?

Click here to watch a video.