Britney Spears Gets Worked Up Watching BF Sam Asghari Workout

Britney Spears is working out her many frustrations ... by watching her BF workout his muscles, while also attempting to play strength coach.

Looks like Brit and Sam Asghari are getting in some QT in the gym, although he's the only one sweating -- at least in the vid he posted. Sam was burning through a set of curls (for the girls) while his workout partner offered up some serious encouragement -- "Squeeze! Pump iron! Do all those things to make all those veins come out. Sexy man."

Okay, so she's more about admiration than inspiration. Whatever ... it's clearly working for both of them.

One thing we know for sure is that Sam's not shy about showing off his physique, and Britney's not shy about gushing over it. We're pretty sure the dude didn't pack a single shirt when they flew to Hawaii last week.

Unclear if they're still on the islands, but it is 💯 clear Brit sounds happy to be hanging with her man in the gym.