The audience started laughing right away at the joke but it took Reese a minute to catch on to the quip. "Oh, my God! No, no, no!" she exclaimed once she got what Letterman was saying.
"I got it now. ...I was having a blonde moment," the Legally Blonde actress explained. "I have a lot of them lately."
Letterman added, "That was the farthest thing from your mind!"
Steering the conversation back towards her daughter, Reese shared that Ava has expressed an interest in acting. "She's very artistic though," she said. "She's sort of a songwriter and she paints. She's wonderful."