Britney Spears Sizzles in a Tiny Bikini While Dancing on a Boat, on Video

Britney Spears is at it again … but this time at sea in a new Instagram dance video — naturally, in a teeny-tiny bikini that doesn’t leave much to the imagination.

Brit posted the new clip to wrap up her weekend … which she spliced together with other dance vids from her house — but this one stood out, as she was getting down on a cruising boat!

As you can see for yourself … Britney is once again giving it all to the camera — this time in a sun hat, and a yellow and green bikini.

The boat makes this latest one unique … not to mention the random dude standing in the back, who appears to be a crew member of the ship — just keepin’ a watchful eye on his passenger. It’s not clear where the video was recorded.

Prior to the dance collection vid, Brit was posting tender moments on IG with her son Jayden … including one of them together captioned “Went to church today !!! Sang and praised !!!”

As you know … Jayden’s the younger brother of 19-year-old Sean Preston. Britney was largely estranged from both boys during their teen years as they lived with dad Kevin Federline.