Sweet Dreams Are Made of Britney Spears

"Sweet Dreams" are made of Britney ... or maybe nightmares?

For her Circus tour in 2009, the star made a provocative music video for Marilyn Manson's cover of the Eurythmics hit, but it was never released, until now.

Mouthing words to one of Manson's signature songs while parading around in what looks like an S&M-style orgy of sorts, this is Spears as you've never seen her.

This is dark stuff ... possibly NSFW. But if you're into this sort of thing - a scantily-clad Britney grinding on people and objects - you'll likely enjoy it.

Britney Spears - Sweet Dreams (Interlude)