'Birds of Prey': How a hard R-rating, Joker breakup and migraines affected Margot Robbie

CANOGA PARK, Calif. – Harley Quinn is not here for organic produce.

On a sunny spring day, Margot Robbie is in full Harley mode on the set of “Birds of Prey (And the Fantabulous Emancipation of One Harley Quinn)” (in theaters Friday) inside Fields Market, her ghostly metallic white body paint a stark contrast to aisles stocked with colorful provisions.

“Ugh,” groans the spikily pigtailed star, tossing fresh vegetables and gluten-free items out of a stolen shopping cart. Clad in a graphic white T-shirt over a neon sports bra and striped denim shorts, Robbie's arm is handcuffed to 12-year-old pickpocket Cassandra Cain (Ella Jay Basco). Cass, as she’s called, mopes behind her in a hoodie.

“Cheez Whiz,” Harley demands, as the young actress grabs a can, adding it to their growing pile of marshmallows, pudding and cookies.

Suddenly, Robbie snaps out of character and into producer mode. “Annnd my cuff came undone," she says, lifting up a wrist to show a dangling silver manacle, the tape used to keep it locked broken. "I just need a bit more tape so it will stick.”

The cast and crew are four days away from completing the shoot for “Birds of Prey,” a project that Robbie, 29, has been manifesting for nearly half a decade. She originated her anti-heroine during 2016’s “Suicide Squad,” a much-hyped mashup of DC Comics characters that crashed and burned upon arrival (let the 27% fresh Rotten Tomatoes score speak for itself).

Still, Robbie’s Harley emerged a fan favorite, and the actress seized upon an opportunity to explore the Joker’s psychotic girlfriend on a deeper level, inviting along DC characters Huntress (Mary Elizabeth Winstead), Black Canary (Jurnee Smollett-Bell) and police detective Renee Montoya (Rosie Perez).

“Birds of Prey" begins by announcing Joker has dumped Harley, whose closest confidante is currently her pet hyena, Bruce. The co-dependent Harley, whose chaotic home life and late-night haunts are unveiled in the film, begins to spin out.

Robbie began producing under her company LuckyChap Entertainment (husband Tom Ackerley is a partner) in 2014 with the goal of promoting women in film. Producing has also allowed her to chart her own destiny in fraught Hollywood waters. (“I, Tonya,” for which Robbie earned her first Oscar nomination playing Tonya Harding, was one of her initial projects.)

Robbie has long talked of the “girl gang” she wanted to display on camera in "Birds of Prey," and with glowing early reactions to the film, many say she achieved it. These Birds sell solidarity over sex, with the requisite dose of Gotham foul play, violence and cursing (Robbie pushed early and hard for the film’s R-rating).

The scene this day hits on a central plot point of “Birds of Prey”: All of Gotham’s mercenaries are after a massive diamond, thanks to a hefty finder's fee promised by mob boss Roman Sionis (Ewan McGregor, giving it his all as the narcissistic villain). Cass' quick hands nabbed it first – and when trapped, she swallowed it.

In the grocery store, the two careen down an aisle of spices, Jell-O and cake mix. “What are we even doing here?” Cassandra whines.

Harley grabs a giant blue bottle of liquid laxatives. “There are two ways that rock’s coming out of you. This way – or this way,” she says, plucking a kitchen knife off a shelf. Cass clutches the bottle. “Also, I’m out of groceries.”

On a break, Robbie sits on a milk crate, snacking on a banana and trail mix. In intervals, she practices a stunt in which she must punch a fellow actor in the crotch. "I have not hit him in his actual nuts, thank God," she laughs, admitting stuntmen she initially practiced with fared worse.

Robbie takes a look in a compact mirror to reapply her own red lipstick. Then she gets back to work.

There are a lot of women on this set. “For me, it was exciting just to tell a woman’s version of this,” says writer Christina Hodson (“Bumblebee"). “I love the idea that these are all women that are born of Gotham in some way who come from that underbelly ... and how strong it makes you to come up in that world.”

Director Cathy Yan unironically watches scenes on video monitors in front of a tampon display in Aisle 5. “It’s quite rare to have this many women behind the scenes,” Yan says later. “Margot and Christina and I are all around the same age, so we looked around like, ‘No adult supervision? OK!’ "

The film, like Robbie's recent films “Bombshell” and “Once Upon a Time in Hollywood,” has shot entirely in Los Angeles, where the actress lives – a convenience she actually hasn’t loved, despite being able to check in at her office and head home at night. She just can’t turn off as much. “I like being able to segregate the experiences and have different chapters with different films in different places," she says.

Robbie has suffered migraines since she was 8; on shoot days, she's learned how to power through them. "It happens on every set. It just sucks," she says. Listening to her schedule is dizzying; the producer/actress refuels every two weeks or so by crashing and sleeping for 10 hours.

Staying well on a frenetic 65-day shoot means “at some point, I end up needing to get an IV drip and pump myself full of vitamins," she says. "I’ve been on the way to premieres with an IV drip in my arm because I’m like, I can’t talk, I can’t breathe.”

But if the pressure is on, it's hard to tell. Every Friday on the set is themed; on Hawaiian T-shirt day, Robbie whipped up batches of piña coladas for the crew. “She’s not ever this close to cracking,” says producer Sue Kroll, pinching her fingers together. “She can juggle a lot.”

In October, Todd Phillips’ “Joker” arrived in theaters to the tune of $1 billion worldwide and 11 Oscar nominations, creating a gritty new narrative around the Joker in a universe that is tonally opposite of the brash, irreverent, neon-hued “Birds of Prey.”

But come January, no one seems to be sweating it.

Contrary to Disney’s Marvel Cinematic Universe, in which movies are meticulously plotted to move within a larger master plan, many of Warner Bros.’ DC Universe movies are rolling out as stand-alone films – the party line being the movies are more versatile and director-driven because of it.

That also applies to the character of Harley Quinn. Robbie, who is currently juggling awards season (she earned an Oscar nomination for "Bombshell") and trips to James Gunn’s Atlanta set for the next “Suicide Squad" movie, confirms Gunn’s film “won't reference things in ‘Birds of Prey.' " (Though in her mind, events of the new "Suicide Squad" take place after “Birds.”)

But this weekend, the Harley show begins.

"You think so much about a project," says Robbie on the set that she built. "And then when you get to the end part, you’re suddenly like, 'Oh, God, I’m not ready for it to be over!' "

This article originally appeared on USA TODAY: 'Birds of Prey': Margot Robbie said no to Joker, yes to R-rating