Jessica Chastain Reveals the Secret Behind Her Terrifying Smile in Mammina — ‘I Learned It at Juilliard’

Even if you’ve only seen the Mammina poster, the smile of Jessica Chastain will likely linger with you, as reassuring in appearance as it is unsettling.

Jessica Chastain and Mammina’s unsettling smile

As a guest on Jimmy Kimmel Live!, the Oscar-winning actress discussed how she managed to craft that expression, revealing to the audience the physical and psychological work behind her character.

To portray the mysterious creature at the center of the film, Jessica Chastain imagined how exhausting it could be for a supernatural entity to maintain human-like appearances. From this insight came a forced smile, accompanied by a muscular tension that even involves the neck. Her face relentlessly strives to seem friendly, yet every muscle tells a very different emotion.

Jessica Chastain’s Acting Lesson Leaves Jimmy Kimmel Speechless

During the interview, Jessica Chastain decided to concretely demonstrate how she achieves that expression. Before a amused Jimmy Kimmel, the actress tensed the facial muscles, stiffened the neck, and showed off the terrifying smile that characterizes her character.

The demonstration reached its most incredible moment when Chastain managed to make a tear fall while maintaining the expression perfectly. When Kimmel asked how she had done it, the actress replied: «I’m a prepared actress, Jimmy!».

Her training at the prestigious Juilliard School in New York played a significant role in shaping her acting abilities. In the past, Chastain had spoken about facing particularly demanding acting exercises, including one that required laughing nonstop for ten minutes, exploring the relationship between the body and emotions.

What Mammina Is About, the New Horror With Jessica Chastain

Directed by Rob Savage, already the filmmaker behind The Boogeyman, is adapted from the novel Incidents Around the House by Josh Malerman.

The story centers on an eight-year-old girl, Bela, whose life is upended by the arrival of an eerie presence she calls Mammina. The creature first manifests itself through the darkest corners of the house, gradually taking on an increasingly threatening role in the family’s daily life.

At the heart of the tale lies a seemingly innocent question that the mysterious entity repeatedly asks the girl: can it enter her heart?

With its unnatural smile and a performance built on careful bodily control, Jessica Chastain promises to give audiences one of the most unsettling characters of her career.