The secret to the films' success, says the British heartthrob, is that they're sexy – without showing a lot of actual sex.
"[Fans] like that moment before [sex] ... the kind of tipping point before it goes over," Pattinson, 24, tells Nightline in an interview airing Monday night on ABC. "I mean, everybody likes that. That's the best part, for a relationship."
If that's the case, Twi-hards will definitely be satisfied when they see Pattinson and Kristen Stewart's characters get closer – but not too close – in Eclipse, which hits theatres June 30.
Still, he acknowledges that there's a fine line between giving fans just enough of what they want and being too old-fashioned territory.
"If there was a hard and fast decision by both [Bella and Edward] saying, 'Yeah we're going to remain virgins our entire lives, it's never going to happen,' I don't think it would be as popular a series," he says.