Johnny Galecki pose in bondage inspired outfits

These sitcom stars aren’t exactly keeping things PG.

Kaley Cuoco shared a saucy behind-the-scenes photo of herself with “The Big Bang Theory” co-star Johnny Galecki each dressed in bondage-inspired outfits.

In the surprising snapshot, Cuoco wore a low-cut red corset and fishnet stockings, while Galecki appeared in a black leather harness with a choker around his neck.

They’ve remained close since their breakup, regularly appearing on each other’s social media feeds, although typically in more appropriate-for-work style photos.

Many speculated last year that the two stars were getting back together after Cuoco divorced from her husband Ryan Sweeting after less than two years together, but both stars quickly shot down those rumors with dueling posts on their respective Instagram pages.

“So sorry to disappoint, but no home wreckers or secret flings going on here,” Cuoco wrote below a photo of her and Galecki bumping firsts. “Me and @sanctionedjohnnygalecki are just the best of buds — Leonard and Penny will have to suffice!!”

Cuoco — a passionate horseback rider — has since moved on to date an equestrian named Karl Cook.