Newly single Kaley Cuoco and her ex Johnny Galecki got extremely close and incredibly weird.

The "Big Bang Theory" costars shared a picture on Instagram where Galecki is seen biting Cuoco's neck. He captured the intimate picture, "Hilarious night out in the LA Arts District w/[Kaley Cuoco] #BFFsbite."

The costars, who dated secretly for almost two years before calling it quits in 2010, have maintained that they are just friends following Cuoco's split from husband Ryan Sweeting this summer.

"So sorry to disappoint, but no home wreckers or secret flings going on here," Cuoco Instagrammed last month. "Me and @sanctionedjohnnygalecki are just the best of buds- Leonard and Penny will just have to suffice!!!"