Britney Spears is just a couple of days into the New Year but she's already in shut-down-the-internet mode ... with this ultra sultry yoga video!!!

She said to hell with custom yoga pants and threw on a purple bikini for a video she made Thursday and posted on her Instagram. It's a jaw-dropper ... she busts a bunch of tantalizing poses ... leaving little to the imagination.

Britney's all about getting incredibly active in 2020. She revealed she ran the 100-meter yard dash in 6.8 seconds. She says she used to run it in 6-flat in high school. Not bad.

This year, Britney says she wants to do a lot more acro yoga and the basics of yoga. She said, "I'm a beginner and it's kind of hard to let go .... learning to trust and letting someone else hold your body!!!"

Britney added, "I have a lot of things I keep bottled up so I have to keep my body moving!!!"

No one's complaining.