David Duchovny and Téa Leoni
07/21/2009 AT 12:30 PM EDT
Just one month after spending Father's Day together on the Malibu shore
with their two children, David Duchovny brought his estranged wife Téa Leoni to Saturday's season-three wrap party for his Showtime series Californication
"David and Téa came in holding hands and got drinks together at the bar," one guest tells PEOPLE. "Then he wandered off to talk to [costar] Pamela [Adlon], but once the gag reel was about to begin he went to find Téa."
The couple have long maintained
a united front, despite having announced their separation
last fall after Duchovny voluntarily entered rehab
for sex addiction.
Sources have told PEOPLE that Duchovny, 48, and Leoni, 43, remain close for the sake of their children, Madeline, 10, and Kyd, 7.
At Saturday's party, held at a private Beverly Hills residence, "They were pretty cozy the rest of the night," says the guest. "They seemed very easy going, not pretentious at all, and at ease."
Monday morning the actor was seen sporting his wedding band as he had a quiet breakfast at Brentwood's Le Pain Quotidien bakery.