We all enjoy a good love story. Nothing warms the heart more than hearing about how a couple fell head over heels for one another – especially when the lovebirds in question are high-profile celebrities.From Richard Burton and Elizabeth Taylor to Brad and Angelina, Eva Mendes and Ryan Gosling, and Ryan Reynolds and Blake Lively, countless high-profile relationships have started (and many more have ended) because actors met on film sets.So what is it about these environments that's so conducive to falling in love?American film director Derek Cianfrance thinks he has the answer. Alicia Vikander and Michael Fassbender met on set of Cianfrance's new film, The Light Between Oceans. They began dating in real life shortly afterwards and have reportedly been together since December 2014. Talking to Vanity Fair , Cianfrance said the secret to creating chemistry on-screen and off is casting actors who are likely to gel. He said he chose Vikander for the role partly because of how he thought she and Fassbender would get on – like "salt and pepper".Cianfrance is something of a celebrity matchmaker – Eva Mendes and Ryan Gosling also reportedly fell in love on the set of The Place Beyond the Pines, another of his films, and they've since had two children together.“I’m making movies about intimacy. My entire purpose on set, and in making a movie, is trying to be [as] truthful as possible to that," said Cianfrance. "One of the first ways to do that is trying to cast the movies right. I cast Michael Fassbender first, I cast Ryan Gosling first, and I have to think who is going to work with this person?”He said he met lots of actors for Vikander's role, but he "felt like her and Michael would go together like salt and pepper."He added: "I thought they would make each other better, they would complement each other as performers. I just felt that they would fit in a beautiful way together. What happens behind the scenes is really none of my business but I’m pleased when anybody finds love.“I’m making movies about love and I’m making love stories and the fact that has happened a couple of times on my movies, I can’t take too much credit for that. I do feel fortunate though that the movies are witnessing something real.”Race you to the auditions for Cianfrance's next film?