Michael Fassbender and Alicia Vikander's real-life chemistry is on full display (and in song!) in this behind-the-scenes clip from their romantic drama The Light Between Oceans

If we didn’t already know that Michael Fassbender and Alicia Vikander fell in love while filming their drama The Light Between Oceans, this exclusive behind-the-scenes clip from the romantic period drama puts a shining spotlight on their undeniable chemistry.

In the video — in which we see brief clips of Fassbender and Vikander improvising their dialogue, movements and obviously enjoying each other’s company — director Derek Cianfrance says that when he was casting the film, he hoped he’d find two actors who made you believe in their romance.

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“When you’re casting a romance, you want it to fit,” he says. “Alicia and Michael ended up working together in such a beautiful way.”

Later in the clip, Vikander, 28, recalls a moment during filming when Fassbender, 39, encouraged her to suggest things for him to do in a scene, which led to him bursting into song.

“The first day, he was like, ‘Give me a new idea!’ ” Vikander says. “That is not many times I’ve had another actor say that, and I just spelled something out.”

The clip then cuts to the moment in question — a very sweet scene where Vikander is working in the kitchen grading cheese and she asks Fassbender to sing her a song. He complies and belts out with what sounds like an Irish folk song.