Paris Hilton & Kevin Federline Party in Las Vegas
12/31/2007 AT 09:00 AM EST
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.