Lizzy Kaplan spills the beans on her first sex scene on her racy Showtime series 'Masters of Sex.' It didn't go quite as planned. (Photo: Getty)

Lizzy Kaplan spills the beans on her first sex scene on her racy Showtime series ‘Masters of Sex.’ It didn’t go quite as planned. (Photo: Getty)

Lizzy Caplan, who by now, could call herself a “sexpert,” tells Conan O’Brien about her first intimate scene with co-star Michael Sheen on the hit Showtime series “Masters of Sex.” It’s not quite what you might think.

Kaplan, 32, plays Virgina Johnson, a “sexologist,” who worked on the pioneering Masters and Johnson study of sex during the uptight 1950s.

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As such, the part calls for regular sex scenes with Sheen, who plays sex researcher William H. Masters.

Shooting the scenes are far from fun and games, and she says her first encounter with Sheen in front of the cameras ended badly say the least.

“Your professionals, your actors, but the first time you do that, isn’t that a nerve wracking experience?” Conan asked.

“Yes, yes,” Caplan replied. “Was it with you two?” she quipped, referring to Conan sidekick, Andy Richter. Yes, she has a sharp wit.

Joking aside, Caplan said she was petrified the first time she shot a sex scene for the show.

“It was weird,” she recounted. “The first season, the first time I take my clothes off with Michael Sheen it’s a scene where we are getting all hopped up on science talk.”

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During the scene, she’s supposed to unbutton her blouse, remover her “brazier” and place Sheen’s hand on her breast.

“As I begin the unbuttoning of the blouse, I’m noticing that I’m very nervous and my hands are kind of shaking,” she says. “And then I grab his hands and I notice that his hands are shaking and a little clammy and he looks bad and nervous and shaky.”

You wouldn’t believe what happened next. Check out the clip below to find out and be sure to follow TheImproper on Twitter for the latest celebrity news. We need and value your support.