'Bridesmaids' actress Rose Byrne welcomed a new bundle of joy, a baby boy named Rocco, on Feb. 1. Partner Bobby Cannavale couldn't keep it for a secret for too long sharing the news with everyone in his latest TV guesting, E News reports.

A bouncing baby boy was welcomed by the three-year couple, the Mirror reports. The news was confirmed after the actor himself revealed it on "The Late Show" with Stephen Colbert, the publication reports.

Sharing the wonderful news, Cannavale said, "I had a baby on Monday, yes." The comedian further revealed how he has been adjusting to having a newborn, saying how much weight he gained for eating.

"You know, I didn't do anything. We [fathers] don't do anything and I'm so tired. I think I've gained 28 pounds since Monday," Cannavale joked as quoted by the news outlet. He added, "I mean, I'm not kidding you. Like, this jacket fit so well, like, last Thursday. But I've been eating so much."

The arrival of their tot made it seem more official when gifts started to arrive in celebration of baby Rocco's birth. Cannavale even revealed he received a gift from actor Al Pacino recently which he disclosed to be a gigantic cake made out of diapers, the publication reports.

Meanwhile, the host of the late night show was quite intrigued at how the couple came up with their baby's name.

The actor jokingly responded, "Actually, yeah, patron saint of the sick...pretty sure. Could be wrong. I'm tired." He shared this reply after Colbert asked if Rocco was named after Saint Rocco.

E News further revealed that as of the moment, the mother-son duo is doing just fine. Meanwhile, the new parents were previously reported to be very excited in welcoming their baby when it was Byrne's third trimester.

"Rose says she feels really well," an insider told the news agency. The source added, "The baby moves all the time. They're both very, very excited." The news comes after the couple were spotted numerous times with Byrne carrying an obvious baby bump, since the two have been tight-lipped about the pregnancy, the news agency revealed.

However, it was only recently that the couple started sharing news about their family life, especially the arrival of their newborn baby Rocco.