Britney Spears Accidentally Reveals Bare Breast in New Dancing Video

Britney Spears' fans are clamoring for her to post her most recent social media vid just one more time ... 'cause they got a glimpse of her breast in her most recent dance routine.

The singer-songwriter shared the clip Thursday ... in which she wore a very low-cut green and white-striped dress. Just as the video starts, she pulls the bust of her dress down -- revealing her bare boob beneath.

She quickly pulls the dress back up and soldiers on -- no embarrassment on her face ... and, she still puts on a sultry show for her social media followers.

Brit runs her hands down her sides, spins around and more ... all of the actions that will have people screaming, "Gimme More."

However, it seems Spears decided she gave too much ... 'cause the impromptu strip show was taken down from social media. Unclear if she deleted it or if IG took it down. Of course, the internet is forever, and the Daily Mail was able to capture it before it went away.

In any case, Britney's looking totally unbothered in the aftermath of her recent plane troubles ... business as usual, at least as it pertains to her steady stream of dance videos.

We broke the story ... sources with direct knowledge told us Britney was flying with her security from Cabo San Lucas, Mexico to LAX when she apparently had a couple drinks on the flight -- all fun and games until we're told she lit a cigarette and started smoking.

Authorities met her when the plane landed, our sources say ... where she received a warning before they sent her on her way.

Britney later explained she found the whole thing "incredibly funny" ... 'cause she wasn't trying to flout aircraft rules -- she really thought she could smoke on the jet.