On Friday night, during an appearance on The Late Show with Stephen Colbert, Bobby Cannavale made a major announcement. The actor revealed that he and girlfriend, Rose Byrne, had welcomed a son on Monday, according to E! News. The couple named the baby boy Rocco. "I had a baby on Monday," the actor told Colbert. "You know, I didn't do anything. We [men] don't do anything and I'm so tired." Cannavale joked that he's "gained 28 pounds since Monday." He also told Colbert that baby Rocco is "doing well." This is the couple's first baby together. Cannavale is also the father of a 20-year-old son, reports People. While Byrne and Cannavale have been fairly quiet about their relationship, the couple did announce that Byrne was pregnant last fall. They reportedly started dating back in 2012. Watch Cannavale talk about the joys of fatherhood and his new show, Vinyl, with Colbert, below.