The actress was joined by Novak, her ex-boyfriend and former The Office co-star, and other pals at a cocktail party Monday at San Vicente Bungalows in West Hollywood.
Novak shared a photo Tuesday on Instagram of himself looking fondly at Kaling during the celebration as she poses with her birthday cake.
Fans immediately remarked on Novak's adoring gaze. The pair played love interests Ryan Howard and Kelly Kapoor on The Office and dated on and off throughout the show's nine-season run.
"SOMEONE LOOK AT ME LIKE RYAN LOOKS AT KELLY," one person wrote.
"Get u a man that looks at u the same way bj looks at mindy," another said.
"The way you still look at her though," one fan wrote.
"Can you guys get married already," another added.
Kaling said in an interview with Good Housekeeping in May that Novak is godfather to her 17-month-old daughter, Katherine. Kaling has not publicly named her daughter's father.
"The truth is that B.J. is so much more like family now than a platonic friend. He's the godfather to my daughter, he comes over like once a week. Sometimes he'll come over just to hang out with her," she told the magazine.
Kaling described her relationship with Novak as "weird as hell" in an interview with InStyle in 2015.
"He is not my boyfriend, but he is not my best friend," she said. "I guess you could describe our relationship as 'romantically charged camaraderie with loud arguments,' but I don't think Facebook would accept this as a new status."
Kaling also celebrated her birthday Monday by giving $1,000 to 40 charities, including RAICES, The Trevor Project and Girls Inc.