A source tells ET that Foxx and Sela Vave celebrated his 52nd birthday at Warwick nightclub in Los Angeles on Wednesday night.
Foxx and the young singer, who arrived together around 12:30 a.m., "kept close to one another at the DJ booth alongside DJ Irie," the source says.
"At one point in the night, Jamie hopped onto the mic for almost an hour, singing multiple hits," including Snoop Dog’s "Drop It Like It’s Hot," the source shares.
The source adds that there were multiple Dom Perignon champagne sent to Foxx’s private table and at one point the entire club sang happy birthday to Foxx.
Foxx exited the club around 2 a.m. with Vave not far behind him, the source notes.
Rumors surrounding Foxx and Vave's relationship began circulating back in August when they were spotted holding hands while leaving a party. The next day, a source told ET that Foxx and Katie Holmes, his longtime girlfriend, "appear to have broken up."
Both Foxx and Vave have denied the relationship, with Foxx calling the speculation "absolutely not true" while on the radio show Big Boy's Neighborhood.
"That girl hangs out with my kids, my young daughter, loves her. My oldest daughter," Foxx explained of his two kids, Corinne, 25, and Annalise, 10. "... I talk to her mom, her parents. So, I know the nature of the business that we're in, so I don't trip on headlines."
"... I got a 25-year-old daughter and I don't date in my daughter's range ever," he added. "... I always try to make sure that my daughter can look at me and say, 'Hey dad, you ain't screwing up.'"
Foxx went on to say that he and Vave have a business relationship only, as he's trying to help her build a singing career.
"But when it comes to that part, and the girls and her, and what I'm trying to do for her as an artist, I feel like I have to be an eldest statesman," he said. "Her uncle, as she calls me, and step in and say 'Hey guys, don't let it be the double standard.'"
"When all the other guys are on the couch, they were hustling and they had dreams," Foxx continued. "And then, when she's now working in this capacity, all of a sudden she's some sort of… I'm using a nice word, using someone to get to the top and that's not the case."
Vave also addressed the double standard in an Instagram post, writing, "For the people who care... here is the TRUE story(swipe)... for everyone else you can keep talking and calling me a whore, slut, home wrecker, thot, gold digger, that I should die, and whatever else you want. Because it doesn’t matter to me, I’m out here to work and do what I love most. #music #killthedoublestandard."