SYDNEY Sweeney has gone topless, posing in just a thong and tights in a steamy advertisement for her brand Syrn.

The Euphoria star posted the ad on her Instagram feed, leaving fans drooling in the comments.

Sydney, 28, posted the video on Instagram on Thursday, showing herself in various stages of undress as she posed for photos for her brand.

The actress first appeared in a pair of tiny white underwear, with a matching bra top.

She posed on a folding chair, arching her back.

The camera then panned to another shot of just her bare butt in a black thong and tights.

She once again posed on a folding chair, swinging her curly blonde hair side-to-side.

In another shot, Sydney is shown lifting a white shirt over her head, exposing her white bra underneath.

She posed laying on the floor with her butt and legs resting on a chair in a brown lingerie set in another frame.

Things got even racier as the ad came to an end, with the actress laying down in bed in various Syrn pieces.

At one point, she was shown stripping her top off while laying in bed.

“Omg! I looooooove this,” one fan posted in the comments.

A second wrote: “So excited!!”

Others posted GIFs with eyes popping out at the camera, kissy faces, and winking.

Up the ante

Sydney has been posting increasingly sexy snaps on social media to promote her brand.

She recently appeared in promotional photos that showed her stripped down to cheeky underwear while pulling down a man’s boxers.

In another, she and her gal pals popped into a convenience store to cause a little chaos.

The group stripped off their clothes, dancing in bras and underwear.

Sydney wore a white bra with a twist in the fabric up front.

She flaunted her figure with her blonde hair in messy waves and sultry glam makeup that included a pink lip and dramatic eyeliner.

Sydney puckered her pout and the camera, sharing a little kiss with the corner store clerk.

She dubbed herself a “midnight snack,” grabbing her breasts and shaking them up and down.