Michael Sheen says he has struggled with talking points while promoting Showtime’s “Masters of Sex.”

“When you’re doing interviews for other shows or films, the questions people ask are, ‘What’s the most extreme or embarrassing thing?’ ” he said at Morgan Library. “When they ask you that on this show, they really don’t want to know the answer.”

Sheen and Lizzy Caplan play the real-life pioneers of the science of human sexuality William Masters and Virginia Johnson on the show, which premiered Sunday.