Vin Diesel Covers 'Stay With Me,' Sam Smith Appropriately Freaks Out

He is Groot, but also a decent singer.

Vin Diesel has quite the falsetto. Who knew?

Backing up a bit, the "Guardians of the Galaxy" star was out promoting his tree-tastic role when Capital FM asked him to sing Sam Smith's certified fresh summer jam "Stay With Me," and the actor happily obliged.

Was he successful? Well, you be the judge:

We think that Vin's vocal work is pretty impressive, especially since he's famous for having a deep, manly-man voice that says things like "I am Groot," as well as the body of an MMA fighter. Basically, we weren't exactly expecting Smith's romantic dulcet tones to work with Mr. Diesel, but hey, we love to be proven wrong.

Oh, and as for Smith? He loved it. Obviously.