Ahead of the debut of "Suicide Squad" on Digital HD, a newly released featurette explores the Joker/Harley Quinn dynamic, and how stars Jared Leto and Margot Robbie captured those "great moments" on screen.

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The key, Robbie reveals, is that she and Leto approached their scenes together fresh, without any rehearsal.

"The Harley/Joker stuff was so unpredictable," she says. "Like, the Squad stuff, we had done so much rehearsal, and we needed to because it bonded us in a way none of us ever expected would happen, obviously. But the Joker stuff, Jared and I really didn't do any rehearsal off-screen -- and it was perfect because then we would get in front of the camera, and I didn't know what was going to happen and he didn't know what was going to happen. I don't think anyone really knew what was going to happen, and that's why I think those scenes were so electric is that they were so unpredictable."

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Leto gives much of the credit to his co-star, saying, "I was lucky in that I had a pretty phenomenal partner in this. I was really lucky to work with her. Incredibly kind, incredibly patient, which you have to be with the Joker in the room."

Written and directed by David Ayer, the film also stars Will Smith, Joel Kinnaman, Viola Davis, Jai Courtney, Jay Hernandez, Adewale Akinnuoye-Agbaje, Ike Barinholtz, Scott Eastwood, Karen Fukuhara and Cara Delevingne. "Suicide Squad" arrives Tuesday on Digital HD, with the Blu-ray following on Dec. 13.