Rose Byrne and Bobby Cannavale welcome a baby boy

Rose Byrne and Bobby Cannavale are the proud parents of a baby boy, one that’s making dad eat like crazy.

The celebrity duo welcomed their first child together -- a little guy named Rocco -- on Feb. 1, the “Vinyl” star revealed on “The Late Show With Stephen Colbert” on Friday.

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“I had a baby on Monday, yes,” Cannavale told Colbert. “You know, I didn’t do anything. We [men] don’t do anything and I’m so tired. I think I’ve gained 28 pounds since Monday. I mean, I’m not kidding you, like, this jacket fit so well, like, last Thursday. But I’ve been eating so much.”

The “Boardwalk Empire” alum also revealed to the host that their son was named after St. Rocco, the patron saint of the sick, according to E! News.

“Pretty sure,” Cannavale quipped. “Could be wrong. I’m tired.”

He noted that his idol/pal Al Pacino sent him a diaper cake for his baby: “It’s for your boy,” he said in a Pacino accent.

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Baby rumors surrounded Cannavale and the “Neighbors” star in October when the Australian actress was spotted at Los Angeles International Airport sporting a perky little baby bump under a loose plaid shirt-dress.

It’s the first child for Byrne, 36, who has been dating the Emmy Award-winning actor since 2012. The couple appeared together in last summer’s Golden Globe-nominated comedy “Spy” as well as “Annie” and “Adult Beginners.” The “Boardwalk Empire” actor also showed his girl some love during his 2013 Emmy acceptance speech, calling the actress out by name and saying she was the love of his life.

It’s the second child for Cannavale, 45, who is already dad to 20-year-old son Jake Cannavale from his previous marriage to Jenny Lumet. Incidentally, Cannavale and his son played a father and son on Showtime’s dark comedy “Nurse Jackie” in 2012.

Follow me on Twitter @NardineSaad.