The unlikely duo of Kevin Federline and Paris Hilton caused heads to turn in Las Vegas over the pre-New Year’s weekend.

On Sunday, the duo partied together for the second night running.

Both were in town to host separate New Year’s Eve parties – hers at LAX, his at Tangerine – but each name attraction started celebrating early, hitting LAX on Saturday and Pure Nightclub on Sunday.

A source close to Federline told PEOPLE that the two hung out in Hilton’s room Saturday after leaving the club.

Still, they seemed less chummy on Sunday at Pure, mingling only briefly before drinking a shot of tequila together.

Say it ain’t so! What are all these rumors flying around that Hayden is hanging out with La Lohan in Italy? I hope these are just coincidences- we wouldn’t want to see Miss Panettiere’s star tarnished by Lilo’s antics …

HAIR!  Holy crap girlfriend!

Lauren was making out with Stephen Colletti, her ex from their days on Laguna Beach and a host for MTV, at LA’s Central on Saturday night.

After arriving together Conrad and Colletti stayed close to each other all night, flirting and chatting. They were spotted making out by the bar after Colletti carried her there from the dance area.