Diaz and Mann co-starred with the 21-year-old model in The Other Woman, and the two confessed they once drew a mustache on Upton's face after she fell asleep on a flight.
"She was fast asleep, like right away, which makes me so mad because I can never sleep on flights," Mann said. "So Cameron and I were up and we're like, 'Yeah, what can we do?' She's like passed out and we decided to draw [a mustache]."
"I'm drawing on her and she does not wake up," said Diaz. "She's like a child. She's like a little baby."
The actresses went on to say they felt so guilty about the prank that they decided to paint mustaches on their own faces as well before taking a picture of their blunder. Diaz felt so bad that she ended up cleaning Upton's face before she woke.
"I washed her face while she slept," Diaz revealed. "She didn't move."
Diaz and Mann also joked about Upton's tame behavior explaining that "Any time we go out, we're always like, 'C'mon, let's go! And she's like, 'I'm going home. I'm tired.'"
You can watch a clip of the actresses appearance on Late Night, and find out their thoughts on kissing Nikolaj Coster-Waldau, below.
Celebrity Breakups and divorces of 2014 [PHOTOS]