The real-life couple star in the drama about a couple who rescue a baby, co-starring Marion Cotillard.
Here's how it all began.
Alicia Vikander and real-life boyfriend Michael Fassbender reportedly met on set of The Light Between Oceans back in 2014, and now, we finally have our first look at the couple sharing the screen together in the film's devastating trailer, premiering exclusively on ET.
WATCH: Alicia Vikander Thanks Boyfriend Michael Fassbender With a Kiss After Oscar Win
Fassbender and Vikander are about to appear in some seriously huge action films -- Assassin's Creed for him, out Dec. 21, while she was recently announced as Lara Croft in the Tomb Raider reboot -- but there is no a** kicking or explosions in this adaptation of the beloved novel.
Instead, you'll probably just cry.
The drama, directed by Blue Valentine helmer, Derek Cianfrance, centers on a lighthouse keeper and his wife, who tragically lose their baby -- only to have one turn up adrift in a rowboat. But it's not all happily ever after when the mother of their "adopted" shows up (played by Rachel Weisz -- this thing is stacked with Academy-beloved actors).
The Light Between Oceans arrives in theaters on Sep. 2, 2016.
Fassbender previously told ET how "very proud" he was of Vikander's phenomenal year, including her first Oscar win. Hear his sweet praise in the video below.