Britney Spears Threatens Porn Star -- I'm So Rich, I'll Destroy You!

Britney Spears' people are trying to bully the woman with whom her boyfriend cheated ... by threatening she's so rich and powerful she'll destroy the woman if she blabs.

It's pretty shocking ... Britney's legal team sent a nasty letter to Cali Lee ... warning her that Brit's former BF David Lucado signed a confidentiality agreement with Britney, and anything he told Cali during their affair must be kept secret.

Here's the thing ... it's BS. Cali is NOT bound by some confidentiality agreement David signed. Period. And Cali's lawyer has told his client she can say what she wants.

In the letter, obtained by TMZ, the lawyer writes, "Rest assured that our client has the resources and the resolve to pursue this matter no matter what the financial cost or outlay in time."