Mindy Kaling inadvertently set off a fresh wave of speculation about her relationship with former co-star B.J. Novak this week with a playful social media post.

On Monday, Kaling acknowledged Novaks 44th birthday on Instagram with a candid selfie showing the pair riding in a car together.

Happy birthday, Uncle B! she wrote in the caption. We love you!

As of Monday afternoon, the post had been liked by more than 125,000 Instagram users and had drawn a plethora of comments alluding to the longstanding rumor that Novak is secretly the father of Kalings daughter Katherine, 5, and son Spencer, 2.

B actually stands for baby daddy, one person wrote.

Added another: You arent fooling anyone!!

Others alluded to the discourse in a less-specific way.

Love your commitment to whatever the hell kind of relationship this is, one person wrote. Always fun seeing the two of you together and happy.