Gwyneth Paltrow and Ben Affleck's physical chemistry was so strong during their relationship that they once got caught having sex on set, a new biography of Paltrow by Amy Odell claims.

FYI, Gwyneth opened up about her relationship with Ben during Call Her Daddy saying that both he and Brad Pitt were "good kissers," and that when it came to who was better in bed, "That is really hard. Because Brad was like the sort of major chemistry, love of your life, kind [of hookup]. And then Ben was, like, technically excellent."

Page Six exclusively learned the sex act Gwyneth Paltrow allegedly enjoyed with her then-boyfriend Ben Affleck — but we’re choosing not to name it. But those in the know won’t be surprised that Affleck was into it; He does love Dunkin’.