Images posted by the Daily Mail show the stars and actress Michelle Monaghan taking to the stage with microphones at the Rockstarz Karaoke bar last week.
Another photograph shows Butler standing among the crowd taking a photograph of the two actresses as they performed.
The trio reportedly treated the audience to renditions of songs including 'You Shook Me All Night Long' by AC/DC and Sheryl Crow's 'All I Wanna Do'.
Moore is currently filming her role of Miley Cyrus's mother in LOL, while Butler and Monaghan are working on biopic Machine Gun Preacher.
