Teresa Palmer's new movie is unlike any rom-com you've seen before.

While most romantic comedies are content to end at the first kiss, Teresa Palmer's new movie, Addition dares to ask a much more interesting question: They fell in love... so what now?

The movie is a refreshing look at what happens when a budding romance hits the high-stakes reality of living and dating with high-functioning anxiety and OCD. It manages to be breathtakingly romantic and deeply sun-soaked while remaining unflinchingly honest about the messy, invisible work of mental health.

The story follows Grace Vandenburg, a brilliant mathematician whose life is governed by a complex system of counting. Whether it's the produce in the grocery store or the number of bites she takes of a sandwich, Grace's world is a rhythmic, orderly fortress built to keep fear at bay.

Watch: The trailer for Addition. Article continues after video.

The order is disrupted when she meets Seamus, a kind and dashing stranger, at a grocery store checkout. After an impulsive moment involving a stolen banana (to keep her count even, naturally), sparks fly. 

But as their connection deepens into something intoxicating, Grace faces a harrowing choice: continue "hiding the crazy" to maintain the perfect facade, or risk letting Seamus see the messy, complicated reality of her rituals.

The film is anchored by a career-best performance from Teresa Palmer, who brings a whip-smart, vulnerable energy to Grace — a character who is as much an anti-heroine as she is a romantic lead.

And we sat down with Teresa herself to dive deep into the 'messy' side of romance and the challenge of portraying a character who is constantly at war with her own mind.

Watching the film, what I personally loved most about this character was how real she felt. She isn't defined by her diagnosis, but she isn't separate from it, either. She's a brilliant academic, a protective sister, and a woman capable of incredible wit, all while navigating a mind that never stops counting.

Image: Roadshow films

And it seems, it was that intricacy that drew Teresa to the role in the first place. 

"Shes' just so complex and nuanced. She's also really funny. I love that she can be all these different shades. She's not just black and white," Teresa told Mamamia. 

"She's brilliant, she's sexy and flirty and wild. And then her anxiety creeps in in this very particular way and I find her very brave." 

In the film, Teresa is joined by an incredible ensemble that brings this world to life.

Joe Dempsie plays Seamus, the heartthrob whose patience and dedication challenge Grace's defense mechanisms. Eamon Farren appears in a brilliant, surreal turn as a fantasy version of Nikola Tesla, Grace's on-again-off-again imaginary boyfriend and intellectual confidant.

Sarah Peirse and Adrienne Pickering round out the cast as Grace's doting mother and nagging sister, creating a family dynamic that feels lived-in and heartbreakingly real.

Image: Roadshow Films

But the thing that caught me by surprise most is the film's ability to balance a conventional rom-com with the heavier themes of mental health. It manages to stay light on its feet without ever making light of Grace's struggle. 

It's this intersection of romance and responsibility that makes the performance feel so vital. For Teresa, the project was as much about getting the representation right as it was about acting. 

"It's unique to her. It doesn't fall under the umbrella of this is how OCD presents or this is how anxiety presents. It's just the way that Grace's anxiety presents. So that was really important to get right. It's unique," Teresa said. 

"There will be audience members who have dealt with anxiety or perhaps have their own labels, who will see themselves in this character and relate to some of the things that she has to navigate. And for that, I feel really grateful and proud that we have this sort of representation on screen."

Image: Roadshow Films

To portray the specific internal rhythm and physical compulsions of Grace's world, Teresa did a lot of preparation, looking far beyond the script to find the truth of the character. 

"I would pull from a few different clips, I read a bunch about anxiety," Teresa explained.

"I also have people in my own life who deal with anxiety. And they were able to really beautifully articulate what it feels like in their body when they find themselves having a panic attack or when they find themselves overwhelmed with intrusive thoughts. I pulled from all these different experiences, and then we made Grace's experience unique to her."

It's rare to find a movie that makes you swoon while also making you feel deeply understood, but Addition does exactly that — reminding us all that love doesn't have to be perfect to finally start adding up.

Addition is in cinemas from Thursday, 29 January, it is rated M.

Feature Image: Roadshow Films.