Celebrity Spotting: Hayden Panettiere, Wladimir Klitschko, David Arquette and Jenny McCarthy all Spotted at XS...

Stars collided at XS Nightclub at Encore Las Vegas for the opening celebration of Night Swim on Sunday night. Fresh off his set at Electric Daisy Carnival in New York, Afrojack took over control of both the dance floor and the venue’s glistening pool for the affair.

Hayden Panettiere, who presented Macklemore and Ryan Lewis’ performance at Tryst Nightclub earlier during the awards show, arrived around midnight with her boyfriend and rumored-fiancé, boxer Wladimir Klitschko. The “Nashville” star was celebrating the series’ upcoming season finale on Wednesday, and danced the night away on stage sipping on vodka cocktails and shots of Don Julio. She stayed until about 3 a.m.

At the table next door on stage was actor David Arquette. The two exchanged greetings before partying in their separate groups.

Jenny McCarthy was also spotted, but was seated inside. The Night Swim event usually caters outside to the pool area but was forced to open the normal indoor club venue due to demand with more than 200 table reservations booked before the club even opened.

Afrojack was in the DJ booth for a three-hour set before he jumped into the pool to splash and interact with his fans.

Click on the photos below to enlarge.

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