Nick Jonas and Girlfriend Olivia Culpo Host Halloween Party at 1 OAK Nightclub in The Mirage

Nick Jonas and Girlfriend Olivia Culpo Host Halloween Party at 1 OAK Nightclub in The Mirage
Nick Jonas
and girlfriend Olivia Culpo hosted a Halloween party and costume contest at 1 OAK Nightclub in The Mirage on October 31, 2014 in Las Vegas (Photo credit: Denise Truscello / WireImage / www.DeniseTruscello.net)

Nick Jonas and Girlfriend Olivia Culpo host Halloween Party at 1 OAK Nightclub in The Mirage
Nick Jonas and Girlfriend Olivia Culpo host Halloween Party at 1 OAK Nightclub in The Mirage

Photo credit: Denise Truscello / WireImage / www.DeniseTruscello.net.

Nick Jonas at 1 OAK Nightclub in The Mirage
Nick Jonas at 1 OAK Nightclub in The Mirage

Photo credit: Denise Truscello / WireImage / www.DeniseTruscello.net.

Nick Jonas arrives at 1 OAK Nightclub in The Mirage
Nick Jonas arrives at 1 OAK Nightclub in The Mirage

Photo credit: Denise Truscello / WireImage / www.DeniseTruscello.net.

Halloween Party at 1 OAK Nightclub in The Mirage
Halloween Party at 1 OAK Nightclub in The Mirage

Photo credit: Denise Truscello / WireImage / www.DeniseTruscello.net.