Birds of Prey aims to give Harley Quinn her wings back after a rough break-up with the Joker this weekend, and actress Margot Robbie has had a steady hand in assuring it’s the emancipation of a lifetime. As a producer on the film, she helped craft the journey her character embarks on in the film, but a strong cast was still needed to flesh out Gotham’s seedy underbelly.

Chris Messina and Ella Basco make up part of that incredible line-up as serial killer Victor Zsasz and young hero-in-training Cassandra Cain respectively. Both performers joined Robbie in explaining their character’s journeys to Screen Rant, as well as secrets from the weirdest audition tape ever.

You guys said it last night yourselves, when you guys introduced the film: badass. I liked it a lot. Margot, this is different this time around for you, because now you were a producer on this film, and you were really involved with the story process. What side of Harley did you want to show that we didn't see before in Suicide Squad?

Margot Robbie: I think we were really curious to explore a version of Harley without the perceived protection of being with the Joker, since she so defines herself by that relationship and lets that relationship define the person she was. But she's come to the realization that that's how Gotham defines her as well: she's Mr. J's girlfriend. And she wants to step out of that shadow.

But she's not cool with it at all. She'll tell you that she's totally fine with it and happy to be a single independent woman. Really, she's not okay with it. She's an absolute mess. But it's fun to watch her go on this journey of like, "Oh, can I do this? I can't do it. Oh, maybe I can do it!" And then finding strength in numbers, really, with the rest of the Birds.

Cassandra Cain makes her debut in this film. By the way, she has great shoe game; those white and gold Jordans were amazing.

Ella Basco: They're vintage.

Rosie Perez, Ella Jay Basco, Margot Robbie and Jurnee Smollett-Bell in Birds of Prey

But I want to know, how does she view Harley? Does she see her more as this maternal figure? Or does she know that Harley has this nefarious endgame?

Ella Basco: I feel like a little bit of both. I mean, in the beginning, Cassandra Cain is so skeptical about anything. She doesn't necessarily really trust anybody in Gotham, because she's been betrayed so much and doesn't really have any parents. But it's kind of like the first impression when Harley does meet Cassandra Cain.

I think she definitely does see her as like a big sister, and she feels like that's needed for her because she's been longing for such guidance in Gotham. She's been so independent, and now she finally has someone to look up to and someone to lean on for advice.

Margot Robbie: For better or worse.

Chris, usually Zsasz is written very much as a straight-up serial killer, but you bring this bounciness to the role. Can you talk to me about where that came from?

Chris Messina: Yeah, I think it was just - it was early on. I made an audition tape for this, and it was something in the... It was a beautiful script, and it was really fun, but there was something in the freedom he kept talking about, "I'm going to free you. I'm going to set you free."

That set me off. I started reading all these books about people that kill and say, "I'm doing it for God. God told me to do it." And so I just tripped out on this prophet-like guy that thought he was almost saving the world by freeing them. Of course, the comic books helped and Cathy and you, when we did a bunch of rehearsals and we just found that.

Ewan's so funny. He's so funny and so charming, so we kind of found this, like, rapport. And what's great about Cathy is, we did a lot of different versions of Zsasz on every take. There was, I think, funnier or sillier or threatening. And so there was a lot of different options, perhaps in there in the edit, and that's the way she went.

Margot Robbie: I mean, probably the most devastating part of this process was how much of Chris' stuff you don't get to see in the movie. Because there is so much gold. At some point it was - you just couldn't put it all in there, but I could happily watch a whole movie of this bizarre version of Zsasz. It just was brilliant.

And that audition he speaks of is one of the craziest things I've ever seen. I'll never forget your audition seen popping up, and all of us being like, "Who is this guy in blue eyeshadow, singing a weird song right now?" It was so, so sick.

I know that Gotham City Sirens was put on the backburner. But do you think that can serve as a sequel to Birds of Prey, or do you like look at that as its own standalone franchise?

Margot Robbie: I don't know. I mean, I definitely would be interested to pursue it, and I'm still interested in that. I don't know where the studios stand on what they want to do next, but that's a relationship I'd love to see Harley in, for sure.

But I think kind of like the comics, a lot of these films can exist on their own. And we know that, "Okay, it's still all Gotham, and it's still the same characters, but it's under a different director's vision."

More: Read Screen Rant's Birds of Prey Review

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