While the longtime couple has been broken up for more than a decade, the two stars continue to be close as they co-parent their daughter, Lily.
Their bond was crystal clear this week when the actress shared an adorable snap of them together on the couch, Beckinsale's head against Sheen's chest.
The two appeared to be at one of the stars' homes. While Beckinsale was dressed casually in a T-shirt and striped pants (with some glamorous stilettos), it was the Masters of Sex alum's ensemble that you probably noticed first.
"So apparently there are two meanings of the word 'perineum,' one being the area of the body between the genitals and anus, and the other, the period of time between Christmas and New Year's Day," the actress captioned the peculiar photo. "I thought I had been clear we were celebrating the second but Michael turned up in an impenetrable onesie just in case he was ambushed by an excitable relative."