Britney Spears' Sushi Date With Hunky 'Slumber Party' Co-Star

Britney Spears might be doing it again ... as in going out with a guy with whom she's been working.

Britney was seen grabbing sushi Saturday night with her co-star from her newest music video, "Slumber Party" ... and this pic of them together is ... interesting.

The stud, Sam Asghari, starred alongside Britney as her love interest. He's a personal trainer -- and he might be attached judging by how fast he took down the post.