While appearing together on the latest episode of Jimmy Kimmel Live, guest hosted by Anthony Anderson, the two joked about a confession Robbie made involving Cena, who co-stars with her in the upcoming James Gunn-directed film TheSuicide Squad.
"I watched WWE when I was growing up. When I was a kid, I loved The Undertaker," the 31-year-old actress explained. "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."
"So I slept in a room for two years with a life-size cardboard cut-out of John Cena in the room," she continued, adding that it would often scare her in the middle of the night. "And then I'd be like, 'Oh, it's just John Cena, it's OK.'"
Minutes after Robbie told the story, Cena was given a life-size cut-out of her, in character as Harley Quinn. "You also have to sleep with that in your room for two years," Robbie quipped. "Just to level the playing field."
See Cena's hilarious reaction below:
The Suicide Squad, whichhits theaters and is available for streaming on HBO Max on Aug. 6, also stars Idris Elba, Sylvester Stallone, Taika Waititi, Pete Davidson, Viola Davis and more.
Though the movie shares two thirds its title and a number of characters with 2016's David Ayer-directed Suicide Squad, Team The Suicide Squad has been adamant this is its own thing. So much so that when Gunn was asked whether viewers need to see the other one first, he tweeted back, "No, you will be just fine."
"It's going to be a whole new thing," Jai Courtney, who reprises his role as Captain Boomerang, told ET. "There's some familiar faces and some old friends and a whole bunch of new people as well."