It’s so easy to hate other people’s children. They’re loud in libraries, they walk slowly on the street, and you’re pressured to give up your seat for them on public transport. If I Had Legs I’d Kick You, a propulsive, agonising drama written by Mary Bronstein, asks a question many of us have always wondered: why is it taboo to hate your own child? After all, an hour spent in a restaurant with a noisy kid on a nearby table is torture enough. So what if that was you on that table, that was your life, and there was no escape?

In If I Had Legs I’d Kick You, Rose Byrne stars as Linda, an exhausted woman in Montauk who’s had enough of motherhood. Her crying child, never seen on screen, has a mysterious, unsolvable illness that involves being fed with a tube, constant crying, and a machine that beeps incessantly. Linda’s husband, also an off-screen presence, is absent through work. While Linda loves her daughter, she occasionally fantasises about an alternate life where she had an abortion. At a low point, Linda accuses the sick girl of being a witch.

Byrne, a 46-year-old Australian actor, has two children herself, and laughs when I tell her I assume every parent finds their offspring annoying. “Having a child is such a mirror to your own limitations,” she says with an upbeat tone. “It isn’t until you become a parent that you know, ‘I have no tolerance for this.’ They’re just being a child. You have to learn. There’s no handbook for it. You’re thrust into the most challenging role of your life.” But the societal handbook dictates that you have to love your child regardless? “The film reflects that expectation around mothers. If you’re having a hard time, and have feelings of disappointment, there’s a lot of shame around those feelings.”

It’s the morning after Byrne did a post-screening Q&A during the London Film Festival. A former London resident, Byrne informs me that she sold her house a while ago (“I loved living in Hackney”) and spent the night in a nearby hotel. I point out that Linda is driven crazy by living in a motel. Is Byrne, an actor who travels for work, an expert in that specific type of loneliness? “You’re the first person to ask about that. And absolutely! Now I have a young family, when I do get to be myself in a hotel, it’s kind of nice. But I used to hate it.”

In comedy movies, excessive close-ups usually indicate a lack of usable footage. However, in If I Had Legs I’d Kick You, the harsh zooms on Linda’s face are a deliberate method of disorientation. From the get-go, the camera focuses on Byrne’s manic eyes and sense of desperation, even pointing up her nostrils. In later scenes, the lens obsesses over her quivering lips, and the way her character scrunches her face whenever she’s on the brink of a breakdown – which happens to be nearly every scene.

“It’s a technical exercise,” says Byrne. “Mary didn’t use any zoom lenses. So the camera was here, and it was 35mm. I could hear it going tick tick tick.” She mimes how close the camera would be to her face. “Sometimes it’s about being still and not breathing, like when she’s so close it’s on my eyelashes.” Before those scenes, did she check a mirror? “No! The character is so disassociated with how she looks. She’s given up.”

It may seem hard to remember, but Byrne was once known primarily as a dramatic performer. Now a household comedy superstar for Bridesmaids, Platonic, and Bad Neighbours, the 46-year-old Australian actor started out in weird indies (The Goddess of 1967) and found a breakthrough in the deadly serious TV show Damages. In a 2015 podcast with Marc Maron, Byrne is met with scepticism when she declares her ambition to delve further into funny material.

The film reflects that expectation around mothers. If you’re having a hard time, and have feelings of disappointment, there’s a lot of shame around those feelings

With If I Had Legs I’d Kick You – the title has no comma, and Bronstein vows to never explain its meaning – Byrne has once again redefined her career with an Oscar-nominated performance that’s both dramatic and comedic. After the roof of Linda’s flat collapses, it’s apparent that everything will go wrong for her. The film, then, isn’t a feel-good romp – Mary Bronstein is married to Ronald Bronstein, the co-writer of Uncut Gems and Marty Supreme, and Josh Safdie is a producer – and Byrne conveys Linda’s ongoing suffering, both in frantic dialogue and exasperated mannerisms. Yet the film is frequently hilarious, even if the laughter is provoked from the unfunniness of Linda’s life. As a punchline, Linda is a therapist herself.

A further testament to Byrne’s acting prowess is her chemistry with atypical co-stars. There’s a child who’s strictly off-screen, a husband (Christian Slater) who’s only on the phone, A$AP Rocky as a nosey worker in her run-down motel, and Conan O’Brien as her therapist. During their sessions, O’Brien’s character is so deadpan and uncaring as a listener that it’s simultaneously tragic and uproarious.

“Conan was a talk show host for 28 years, and he sat there listening to people talking about themselves,” says Byrne. “And in our movie, he’s not listening to this girl! He’s so burned out that he’s actively not helping.” Jazz is referred to as the notes you don’t play. Is there something similar with Byrne and O’Brien knowing what comedy beats to avoid? She mulls it over. “I think comedy is harder, because it’s more subjective, whereas we can all collectively agree on what is sad.”

Likewise, Byrne acknowledges that A$AP Rocky brought a different energy to set. “That character has to be so effortlessly cool and charming. The movie is so tense, but it’s a relief when he comes because he’s so relaxed in his body. You can’t teach that. I loved our scenes, because it’s like: what does he want?” The rapper plays James, a playful, patient stranger whose chemistry with Linda has echoes of Byrne and Seth Rogen’s duo in Platonic. “[Linda and James] are not friends, but they’re not not flirting. It’s weird. She’s so dismissive of him. He’s intrigued and bored and like, ‘What’s this bitch doing? Why is she so mean to me?’”

Byrne is still marvelling at the feedback to a film that had its world premiere in February 2025. The previous night, at the Q&A, a young woman in the audience told Byrne and Bronstein she wanted to one day become a mother. “She said, ‘I thought this movie would scare me, but it gave me the confidence to do it, because it’s talking about what the reality is.’ Mary was like, ‘Wow, we never get that response.’”

In interviews, Bronstein has insisted that the film is about doom, not stress. “I understand both,” says Byrne. “The tension of the film is so singular and extraordinary. But I love the existential doom around Linda.” When I ponder if the film could have been about struggling in Hackney, Byrne responds, “The film is universal. Are you struggling in London? The movie is about struggle, too. Mary pitched it like: ‘Imagine the worst thing that’s ever happened to you in your life, and then imagine the worst thing that’s happened to you today. It’s sort of in between.’”

If I Had Legs I’d Kick You is out in UK cinemas now.