Greta Gerwig's reaction to Michael Cera's Allan scream in Barbie has been revealed in a new behind-the-scenes video.

In a new behind-the-scenes video (courtesy of Entertainment Tonight), Gerwig is seen filming one of Cera's Barbie scenes. During the scene where Ryan Gosling's Ken runs into a tide, causing him to fly backward, Allan belts out of scream. Gerwig is seen behing the camera, laughing so hard that she falls onto the floor.

Michael Cera gives a scene-stealing performance in Barbie as Allan. The one-of-a-kind doll pops in and out of the movie, never failing to put a smile on viewers' face. This includes a bada*s fight scene at the end. Known for his roles in Superbad, Juno, and Scott Pilgrim vs. the World, it's great to see him have a scene-stealing performance once again.

Barbie has been a box office smash hit. The Gerwig-directed film is the highest-grossing film directed solely by a woman. To date, the film has grossed over $1.4 billion worldwide and hit digital platforms just last week. The film follows the titular doll (played by Margot Robbie) on a journey of self-discovery with Ken after an existential crisis. Issa Rae, Kate McKinnon, Emma Mackey, Dua Lipa, America Ferrera, Simu Liu, Kingsley Ben-Adir, John Cena, Helen Mirren, Rhea Perlman, Ariana Greenblatt, and Will Ferrell also appear in the film.

Greta Gerwig is an Oscar-nominated director known for Lady Bird and the 2019 adaptation of Little Women. Coming up, she will co-write the script for Marc Webb's live-action remake of Disney's Snow White.

Barbie is in theaters and on digital platforms now.