While Paris Parties, Doug Cozies Up to New Blonde

Paris Hilton might be doing a bit of party-hopping to keep her mind off her split with Doug Reinhardt — but that can't work out too well when she happens to run into him while he's making out with a new blonde!

An eyewitness tells OK! Doug was kissing his new gal last night at My Studio just as Paris arrived.

"Paris came in wearing a leopard print dress with her girlfriends," an onlooker tells OK!. "It was so funny!"

OK! GALLERY: PARIS PREENS & PRANCES ON HER NIGHT OUT

So did Doug even bat an eyelash at the appearance of his ex? Sort of, says our source.

"He glanced at her as she was walking by."

Ouch! Could this be the same blonde bombshell he's been seen with lately?

OK! EXCLUSIVE: PARIS & DOUG'S REBOUND RIVALRY

For her part, Paris pretended Doug didn't exist, partying for a few hours and leaving the club... all without a word to her ex.

Double ouch!

OK! EXCLUSIVE: DOUG TELLS OK! HE AND PARIS ARE OVER... AGAIN!