The Room actress has been dating the 36-year-old former Phantom Planet frontman since 2013. At the 2016 Screen Actors Guild Award in January, Larson sweetly offered up an "I Love You" to her beau during her acceptance speech for Outstanding Performance by a Female Actor in a Leading Role.
"Oh man, I mean, he's the other half of the equation -- how can you explain support?" she exclusively gushed to ET about Greenwald backstage. "I mean, it goes beyond anything. He's just my person, he's my best friend."