Rose Byrne and Bobby Cannavale welcome a son

Rose Byrne and Bobby Cannavale are new parents after welcoming a son.

During his appearance on The Late Show with Stephen Colbert, Bobby revealed his long-term girlfriend Rose gave birth to a son named Rocco on Monday (01Feb16).

"I had a baby on Monday, yes," the Ant Man star shared. "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."

When host Stephen asked whether the couple had named their son after Saint Rocco, Bobby joked, "Actually, yeah, patron saint of the sick... pretty sure. Could be wrong. I'm tired."

The notoriously private couple reportedly started dating back in 2012, and Bobby revealed their relationship at the 2013 Emmys when he dedicated his award for Outstanding Supporting Actor in a Drama Series to Rose, who he called "the love of my life".

The pair managed to keep Rose's pregnancy under wraps until the Bad Neighbors star debuted her baby bump back in November (15).