Kristen Stewart is the latest Hollywood A-lister to fall for a man on-set. So what is it about making movies that results in stars making moves of a different sort? 
Ever had an office crush or a holiday romance? Well, combine the two and you’ve got some idea of what sparks the on-set affair. “It’s the shared experience,” explains celebrity relationship expert Dr Gilda Carle. “You’re working incredibly long hours, often in remote locations for months on end – it’s natural to form a bond.” And it must help that most people in Hollywood are pretty fanciable. Fabulous investigates the phenomenon…

Angelina Jolie, 37

Brad Pitt, 48, Mr & Mrs Smith; Billy Bob Thornton, 57, Pushing Tin; Jonny Lee Miller, 39, Hackers

Angelina and her on-screen beaus, from left: Jonny Lee Miller and Billy Bob Thornton
“Brangelina” was born when Pitt and Jolie’s on-set chemistry spilled into real life. But this wasn’t the first time for Ange. In 1996, the actress married Jonny Lee Miller after meeting him on the set of Hackers. Then in 2000, she eloped with Pushing Tin co-star Billy Bob Thornton (after he ditched his girlfriend, Laura Dern). “It’s a case of ‘I want, I get!’ with Angelina,” explains Dr. Gilda. “She feels she can do whatever she pleases, and this confidence can be very appealing.”

Angelina with Brad Pitt

Jessica Alba, 31, and Cash Warren, 33, The Fantastic Four

Giving hope to runners (and average men) everywhere, Jess met director’s assistant Cash on the set of The Fantastic Four in 2004. They married four years later and now have two children. “Jess clearly wanted to settle down with someone she could trust,” explains Dr. Gilda. “Step in Mr Average. She’s definitely the better-looking, more successful partner, and possibly wanted a more normal life. But Cash is now a big Hollywood producer, so maybe she spotted his potential.”

Julia Roberts, 44

Daniel Moder, 45, The Mexican; Lyle Lovett, 54, The Player; Kiefer Sutherland, 45, Flatliners; Dylan McDermott, 50, Steel Magnolias; Liam Neeson, 60, No Satisfaction

Julia with Kiefer Sutherland
Despite having Brad Pitt on set, it was cameraman Daniel Moder that Julia fell for while working on The Mexican in 2000. “After years of drama in her love life, Julia shunned egocentric actors for someone normal,” says Dr. Gilda. “And the fact they’re still together, 12 years and three children later, means the strategy worked.” Before Daniel, Julia dated co-star after co-star, including Kiefer Sutherland (who she dumped just days before their wedding in 1991).
“Celebrities can’t meet people in the usual ways,” says Dr. Gilda. “The film set is often the only place A-listers come into contact with new people – and it’s such an intense way to meet someone. You’re doing everything together, and the rest of the world is a long way away.”

Julia’s gents: Dylan McDermott, left, and husband Daniel Moder

Jennifer Aniston, 43

Justin Theroux, 41, Wanderlust; Gerard Butler, 42, The Bounty Hunter; Vince Vaughn, 42, The Break-Up

Jen and Justin Theroux
In the wake of her split with Brad Pitt (him again) in 2005, Jen’s been linked to nearly all of her male co-stars. First she was papped snogging Vince, then she canoodled with Gerard on the red carpet, and now it’s been announced that she and Justin are engaged. “I wonder if, after being so devastated in public, Jen is subconsciously trying to show the world that she’s loved,” says Dr. Gilda. “With Brangelina always in the news, Jen’s relationships with her co-stars have ensured she’s stayed in the limelight, too.”

Jen and her co-stars, from left: Gerard Butler and Vince Vaughn

Aaron Johnson, 22, and Sam Taylor Wood, 45, Nowhere Boy

Celeb-land was shocked when then-19-year-old actor Aaron started dating the 42-year-old, mother-of-two director. But the couple proved the sceptics wrong and are now married with two children. “When a very young man falls for an older women he’s normally looking for a mother figure,” explains Dr. Gilda. “Add in the fact that she’s his director and in control of his career at that point, and you can see who’s the dominant partner in their relationship!”

Miley Cyrus, 19, and Liam Hemsworth, 20, The Last Song

Miley fell for Aussie actor Liam when he played her on-screen boyfriend in 2010’s chick flick The Last Song. After two years of being on and off, the pair are now engaged. “It’s common for actors playing lovers to experience those feelings in real life,” explains Dr. Gilda. “You’re trying to inhabit that character, and you’re filming intimate scenes together. It’s not surprising that the line between fantasy and reality blurs. But when filming wraps, it can be hard to sustain a relationship.” Fingers crossed for this pair, then!
Photography: Allstar, PA, Getty Images, Xposure, Touchstone Pictures