LAS VEGAS, NV - FEBRUARY 13: Mischa Barton (L) and mother Nuala Barton attend Marquee Nightclub at The Cosmopolitan of Las Vegas on February 13, 2012 in Las Vegas, Nevada. (Photo by Denise Truscello/WireImage)
LAS VEGAS, NV - FEBRUARY 13: Mischa Barton (L) and mother Nuala Barton attend Marquee Nightclub at The Cosmopolitan of Las Vegas on February 13, 2012 in Las Vegas, Nevada. (Photo by Denise Truscello/WireImage)