- "Off camera, Jason is a very cool, chill guy," says Chris Marrs Piliero
- "He's been on a diet and he worked out," Piliero says
- "Britney is stunning in the video," he says.
In the video for her single "Criminal," Britney Spears shares passionate scenes with her real-life boyfriend more than two years, Jason Trawick -- and things seem to be going equally well off-screen, the video's director tells PEOPLE.
"It's an interesting situation, filming intimate moments like that between two people who, off-screen, would be sharing moments similar to that," says Chris Marrs Piliero, who also directed Spears in her video "I Wanna Go."
"Off camera, Jason is a very cool, chill guy," he added. "Which goes really well with Britney because she's so much the same ... she's a really sweet girl that, when the cameras aren't rolling, she's just chilling out. They would just [hang] out together."
In the video, shot over two days in London, Trawick plays the bad-boy love interest who takes Spears's character away from her abusive boyfriend. As they embark on a crime spree, the couple -- who recently shot down rumors of an engagement -- also finds time to show some skin in a few sex scenes.
"When you're looking at that final kiss for the shootout, it's a loving very passionate kiss," Piliero says. "That was important to the video and that was passionate and natural on their end. That's a real moment between them."
"It was really painless," he added of filming their clinches. "I feel like all three of us had a really comfortable level of communication and trust."
Early on, however, Piliero wasn't thrilled about having Trawick, who doesn't have an acting background, in the video. "I don't think I was ever psyched going into it," he says. "But he did an awesome job."
Trawick, 39, also showed up on the set with a new ripped physique, and his chiseled look attracted a lot of notice.
"He's been on a diet and he worked out," Piliero says. "I'm not sure what his secret is, but he went pretty hardcore with it and those are the end results."
As for Spears, 29, who helped develop the concept for the video and offered ideas throughout filming, Piliero says that after years in the business she's at the top of her game.
"Britney is stunning in the video. She's definitely keeping a workout routine -- you can definitely tell she's doing a great job staying in shape," he says, adding, "She has these great expressions she makes and this charming sparkle on her face. She eats you up with her looks."