Britney Spears Dances to a Justin Timberlake Song on Boat

Britney Spears is back on vacation and doing a little throwback, romantically speaking, as she shakes her assets in a bikini ... while listening to some Justin Timberlake!

The Princess of Pop was cheezin' hard while rocking green swimwear on a boat. Brit dancing on her Instagram is nothing new, but this time she was groovin' to Timbaland's 2009 hit "Carry Out" ... which, of course, features that guy she dated for 3 years.

As you know ... BS and JT aren't on the best of terms -- she dragged him in her 2023 memoir "The Woman In Me" and called him out for making her look like a cheater when in reality, they were both guilty of infidelity.

Only a snippet of "Carry Out" is heard in the clip ... so perhaps, she cut it off before Justin's part started. Or, perhaps she's moving on from the "Toxic" drama ... and simply likes the catchy tune.

Regardless, Brit looks unfazed by the song ... and is grinning from ear to ear as she dances and talks about going snorkeling in crystal clear water. It's not clear where she's soaking up the sun, but she likened it to Turks and Caicos.

As you know ... Britney's always dancing in the many videos she posts on social media. Just the other day, she was shakin' what her momma gave her while gushing about baking bread ... and before that, she treated fans to some vocals.