Whoops! For Father’s Day, John Mulaney posted a sweet pic of himself and his 2-year-old  son, Malcolm, hanging out in the kitchen together on Instagram, only to delete it from the photo-sharing app. But the standup comedian, 41, wasn’t fast enough. Fans spotted the silver  band on the former Saturday Night Live writer ’s wedding ring finger, sparking speculation that he and girlfriend Olivia Munn have secretly tied the knot.

As Life & Style has previously reported, John became Olivia’s rock after she was diagnosed with an aggressive form of breast cancer last April, resulting in five surgeries, including a double mastectomy and a hysterectomy. “It would’ve felt like climbing an iceberg without him,” the actress, 43, gushed. “I don’t think that he had a moment to himself … between being an incredibly hands-on father to Malcolm and then going to and from the hospital.”

Having stuck by each other’s side in sickness and in health, “Olivia and John were already married in every other sense of the word,” a source close to the couple exclusively admits to Life & Style. “But now it’s pretty clear that they’re officially married, too.”