Watch Joe Jonas Ruin a Valentine's Day Dinner Proposal!

Here's a tip for guys: Don't invite Joe Jonas to serenade your girlfriend when you're going to propose. Especially if you don't want it to end with a slap!

OK! GALLERY: JOE JONAS TAKES A SUNNY STROLL IN L.A.

Joe teamed up with Funny or Die for a funny Valentine's Day video where he "helps" a guy propose to his girlfriend.

But the dinner ends with a slap in face — given by Joe! Looks like this JoBro can hold his own!

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Watch the "Joe Jonas Valentine" below!