Catherine Hardwicke Discusses Robert Pattinson, Kristen Stewart Chemistry

'Twilight' director recalls warning Pattinson not to get involved with his then-underage co-star.

As if photos of Kristen Stewart and Robert Pattinson holding hands in Paris and snuggling at concerts in Canada weren’t enough to convince fans that the two are more than just co-stars, “Twilight” director Catherine Hardwicke now says that she always kind of knew there was a chemistry between the pair.

In fact, from day one she warned Pattinson about his feelings for the then underage actress. “After I cast him, I told Rob, ‘Don’t even think about having a romance with her,’ ” Hardwicke told Time. “She’s under 18. You will be arrested.”

On the other hand, Hardwicke said she never saw anything romantic go on between the two in real life. “I didn’t have a camera in the hotel room. I cannot say,” Hardwicke explained. “But in terms of what Kristen told me directly, it didn’t happen on the first movie. Nothing crossed the line while on the first film. I think it took a long time for Kristen to realize, ‘OK, I’ve got to give this a go and really try to be with this person.’ ”

Earlier this year, Hardwicke told MTV News about how she tested the chemistry between her potential stars by filming them kissing in her own bedroom.

“They had to do it three times,” she remembered. “The first time, they went a little too far, and I was like, ‘I can’t show this to anybody at the studio!’ After we finished the whole thing and we had met bachelors one, two, three and four, Kristen said, ‘It has to be Rob.’ She basically threatened me.”

The director never had any doubt that Pattinson and Stewart were meant to play Bella and Edward, even when others, like the studio, had their doubts about her casting decisions.

“He was disheveled,” Hardwicke told Time. “He was a different weight. His hair was different and dyed black. He was all sloppy. The studio head said, ‘You want to cast this guy as Edward Cullen?’ I said, ‘Yeah.’ And he said, ‘Do you think you can make him look good?’ I said, ‘Yes, I do.’ ”

MTV delves deep into the “Twilight” universe with two can’t-miss specials: “Love Bites” chronicles the budding rumored romance between Robert Pattinson and Kristen Stewart on Monday at 10 p.m. ET/PT, while “New Moon Revealed” will feature die-hard fans as they gather to meet the saga’s stars Monday at 10:30 p.m. ET/PT.

Check out everything we’ve got on “The Twilight Saga: New Moon.”

For young Hollywood news, fashion and “Twilight” updates around the clock, visit HollywoodCrush.MTV.com.