Spoiler alert! Keep reading if you want to know what happens...
"It does actually literally get more physical [in Breaking Dawn]," Stewart tells Access Hollywood, referring to the couple's sex scenes. "It doesn't get more action-packed … [But] they definitely get more physical. Well, they get married."
The film's screenwriter has said she plans to show Stewart's character, Bella, giving birth, so how steamy will the pre-baby scenes get?
"Well, they're man and wife now," Stewart says leadingly. "They have a kid and stuff too, so, I guess to get there that happens."
She adds with mock excitement, "We totally have sex – finally!"
For his part, Pattinson jokes that one moment of the Edward and Bella romantic scenes in the book stuck out to him.
"I'm looking forward to the pillow-biting scene," he says with a laugh. "I thought that was so funny. Of all the random things too do, really? He bites the pillow."
Plus, now that he'll be showing more skin, "I can't wait to get all my body makeup on," Pattinson says, "to be especially pasty looking."