Nick Jonas & Olivia Culpo Strike a Pose at Big Knockout Boxing!

Nick Jonas is handsome in a button-up vest at the inaugural event for Big Knockout Boxing at the Mandalay Bay Events Center on Saturday night (August 16) in Las Vegas.

The 21-year-old entertainer stayed close to his girlfriend Olivia Culpo on the red carpet before the match.

PHOTOS: Check out the latest pics of Nick Jonas

Also at the event was model Nina Agdal, Pretty Little Liars actress Ashley Benson and personality Maria Menounos.

“On my way to @bkb ready to see some knockouts #BKB @DIRECTV,” Nina tweeted on her way to the event.

10+ pics inside…