12/18/2011 at 12:00 PM EST
's birthday weekend was quite a "thriller"!
star, who turns 48 on Sunday, was joined by longtime love Angelina Jolie
and their six children in Las Vegas Saturday night to experience the Michael Jackson The Immortal
, the Cirque Du Soleil touring show
"They had great seats, sitting right beside the stage," a source said. "They really seemed to enjoy the show. The performers didn't know they were there and a few of them recognized them while they were on stage, so it was pretty exciting."
After giving a standing ovation, Pitt, donning round glasses, Jolie, wearing a light grey dress, and the children left just as the cast gave final bows. The family spent the night at the lavish Four Seasons.– Mark Gray