As Britney Spears faced the judge in her kids’ custody hearing on Thursday – winning a small victory by gaining supervised overnight visitation rights – her ex-husband Kevin Federline spent time shooting scenes in Wilmington, N.C., for episode seven of his guest spot on One Tree Hill.

Later Thursday night, Federline arrived at a club called The Liquid Room in downtown Wilmington, where he partied like a rock star in the VIP area, ordering up rounds.

“He’s drinking Jack and Coke and Patrón. That’s all he drinks,” a cocktail waitress said.

When the deejay spun his ex-wife’s new song, all eyes darted to Federline, clad in a white T-shirt and jeans and wearing noticeable bling. “When ‘Gimme More’ came on, I looked at him, and he didn’t have any reaction. He wasn’t dancing,” said a reveler in the club.

One observer said the VIP area is normally very quiet, “but when K-Fed is there, he brings the whole posse.”

As for how Federline enjoyed himself, “He seemed happy. He seemed like he was having fun – he wasn’t upset,” she said.

Federline and his mini-entourage stayed until after the club closed at 2 a.m.