Leave the movie at the bedroom door, say Cannes Film Festival couples

Katharine Hepburn and Spencer Tracy, Humphrey Bogart and Lauren Bacall, Joel Coen and Frances McDormand.

Movie magic often has real-life love stories behind it, but star couples at this year's Cannes Film Festival said you must tread carefully when mixing work and romance.

Spanish Oscar winners Penelope Cruz and Javier Bardem have teamed up on nine movies.

After the premiere of their thriller Everybody Knows, which opened the festival, Cruz said drily that while she enjoyed working with her husband, she would not want to do it all the time.

"It is not something we plan on doing every two years," she said, adding that the couple, who have two children, were paid equally for the film and have strict rules about leaving the push-and-pull of their personal relationship far from the set.

"It would not make your life better, I think, if you used certain things from your private life (on a film)," said Cruz.

China's Zhao Tao has made six films with her husband, director Jia Zhangke, including Mountains May Depart.

Their latest is another Cannes contender, Ash Is Purest White.

She calls her husband "Director Jia" while shooting, just like the rest of the cast.

"When I come home and we get back to our own family, we have nicknames for each other - but that is something that just belongs to both of us privately," she said.

Zhao said their relationship has grown more "dynamic" and collaborative since they made their first picture together, Platform, in 2000.

"Back then, if the director thought a scene was good, I tended to think, 'Yeah, it is good enough,'" she said.

"Now, it is more of a dialogue about the characters - how I want from a female perspective to make a character come alive. I think he is very responsive to my opinions and suggestions."

Jia, who won the Golden Lion top prize at the Venice Film Festival in 2006 for Still Life, said their sometimes hard-fought consensus covered even ostensibly trivial details like costumes.

He said their shared love of US film-maker Quentin Tarantino's Kill Bill movies led the couple to borrow some of the colours of its wardrobe for Ash Is Purest White.

Another on-screen, off-screen partnership that made a splash at Cannes this year was Spanish director-producer pair Raul de la Fuente and Amaia Ramirez, who presented their animated docudrama Another Day Of Life after a few cinematic kisses for the cameras.

Ciro Guerra and Cristina Gallego also managed to co-direct their critically acclaimed Colombian narcodrama, Birds Of Passage, despite the recent end of their romantic relationship.

It is often a cinema passion project that brings lovers together, as with Abu Bakr Shawky and the producer of his debut feature Yomeddine, Dina Emam.

"We didn't start dating until maybe right before production," Emam said.

The film, set in an Egyptian leper colony using non-professional actors who were not able to read or write, proved to be more of a bonding experience than they bargained for.

The two survived a "really terrifying" shakedown by amateur security guards, bureaucracy and the vagaries of crowdfunding a project that surprised everyone - particularly the film-makers - by getting into Cannes' vaunted competition.

"It was a gruelling shoot. I can't sugarcoat it," said Shawky.

Emam agreed: "There is no amount of planning that could have prevented the things that happened on this shoot - I think maybe we were a little cursed."

But after their baptism of fire, Shawky and Emam decided they were ready to take the next step.

"As soon as we were done with the film, we decided, 'I think we've gone through the hardest thing we will ever go through in our lives - I think marriage will be a piece of cake,'" she quipped. - AFP