Robert Downey Jr. (Frazer Harrison/Getty Images for BAFTA )

In an interview on “The Tonight Show with Jay Leno,” the former bad boy actor was asked if he knows the sex of his first child with wife Susan, due in “late February.”

“I am not permitted to discuss it,” Downey told Leno. “I keep dropping the ball everywhere. [My wife will] say don't tell your cousins until I — and then I tell them.”

No problem, Robert. We can all respect your wife’s desire to have a little privacy.

“I can’t say a word. We’re having a boy. [Expletive]. I did it!” Downey said in a sudden “cat out of the bag” burst. “Pardon me.”

Downey, who has an 18-year-old son from his first marriage, later joked, “I am gonna have to see my wife some time after doing this segment with you, and I think I'm already in trouble.” Maybe just a little.

Watch the interview below.