"Let's Get It On" isn't the kind of song most women wants to listen to while they're in labor. And yet, Ryan Reynolds thought it might lighten the mood when his wife, Blake Lively, was about to give birth to their daughter, James Reynolds, in December 2014. He was very wrong.

Ryan joked about Blake's reaction to his song selection during an appearance on NBC's Late Night Wednesday. "I jammed a little Marvin Gaye's 'Let's Get It On.' It was like steak knives came out of her eyes," the actor said. "Like, 'Are you f--king s--tting me right now?' Real bad, yeah. But she was a mercenary. I think I just caught her right in the middle of a contraction."

In fact, he added, "She was making jokes the entire time."

Host Seth Meyers broached the subject with his guest given that he is currently expecting his own firstborn child with human rights lawyer Alexi Ashe. So, what tips did Ryan have to share? "Do the dirty work, man. You gotta do the diapers. You gotta do the middle of the night thing," he advised. "A human being will exit your wife, so she's done enough. Just change the diapers."