06/18/2012 AT 6:00 AM ET
The basketball star and four guy friends recently popped into a Perrier-Jouet-sponsored bash at hotspot Bagatelle in New York City.
? Providing music for the night: Beyoncé’s sister Solange, who was deejaying.
Humphries and his group, meanwhile, headed to the back of the bar for a drink when they got in, an onlooker tells PEOPLE.
“Kris posed for a camera phone with one partygoer,” the source says. “They stayed about 40 minutes before taking off.”
– Jessica Wedemeyer