Say it ain’t so, Blair!

Gossip Girl beauty — and normally strait-laced actress — Leighton Meester has found herself at the center of a sex tape scandal.

Word is a recording of the twentysomething star engaging in a variety of sex acts with a boyfriend is being shopped to various adult film studios around California.

We hear company called celebhotline.com is negotiating an deal to release the video.

“We’ve seen the tape and we’re hoping to close the deal,” say Kevin Blatt, a rep for the website.

TMZ.com writes: We’ve learned a Meester tape is being shopped around town. It was shot a few years back, and shows Leighton in mostly innocuous though nude scenes — with several big exceptions … one involving her very talented feet.

Leighton — who is best known for her role as Uptown Girl Blair on The CW’s cult hit Gossip Girl – will release her debut pop-rock LP in September.