Oscar Isaac Explains His Viral Red Carpet Moment With Jessica Chastain

Oscar Isaac‘s explanation for that viral red carpet PDA moment with Jessica Chastain is simple—and squeamish: They’re worms!

Last September, the Scenes From a Marriage co-stars showcased their major chemistry at the event while promoting their HBO limited series. The co-stars held hands and wrapped their arms around each other while posing for the cameras, while Isaac also appeared to kiss and sniff Chastain’s inner upper arm. On SiriusXM’s The Jess Cagle Show this week, Isaac compared himself and the actress to…flatworms.

“You know, you can cut them into like a hundred pieces and they will grow a whole new worm out of the little piece,” the Moon Knight actor explained. “So they’re basically kind of immortal and they’ve been doing work at the cellular level where they’re seeing that the cells kind of talk to each other through electricity and kind of decide, ‘Okay you’re going to make the head.’ ‘All right, I’m going to make the tail’…they’re communicating through some sort of like electro kind of magnetic situation.”

Isaac concluded, “That’s how Jessica and I kind of talk to each other. We’re just like, little flatworms.”