Margot Robbie had an embarrassing secret to tell her co-star of “The Suicide Squad” John Cena when they met.

Robbie, Cena, and director James Gunn chatted to guest-host Anthony Anderson on Wednesday’s “Jimmy Kimmel Live!”, with the actress admitting to previously sleeping in the same room as a life-size cut-out of the wrestler.

She shared, “I watched WWE when I was growing up, when I was a kid I loved the Undertaker.

“And then obviously when I was a teenager I stopped watching. But then, as a late teen, early 20s, I had a boyfriend who was obsessed with John Cena — so much so that he dressed as John Cena for his 21st birthday and had a cardboard cut-out in his bedroom.”

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“So I slept in a room for two years with a life-size cardboard cut-out of John Cena in the room,” she went on, adding that sometimes she’d be startled if she were to wake up in the middle of the night.

Robbie laughed: “And then I’d be like, ‘Oh, it’s just John Cena, it’s OK.'”

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Despite considering whether or not to tell Cena, who came to the interview dressed in his Peacemaker outfit, about her little secret, she admitted she spilled the beans “five seconds into meeting him.”

Cena was then presented with a life-size cardboard cut-out of Robbie’s “The Suicide Squad” character Harley Quinn.

“You also have to sleep with that in your room for two years,” Robbie told Cena, “just to level the playing field.”

Clearly up for the challenge, Cena simply replied, “OK.”

See more in the clip above.