Giancarlo Ruiz plays twins in the movie and the way he prepared for the role was very methodical. He used soundtracks for each scene and each character to get in the right mood. He had a 10 step process of how Hector would become Rafael, depending on the timeline of the story he would put a number on the stage of the transformation of the character and would have a special body posture for each one.
The inspiration for the eccentric nature and wardrobe of Rafael came from an uncle of Salomon's wife, Sara. In the scene where Hector is having breakfast at Nicole's, the pair of glasses which he is using belong to the late uncle, Moises Cohen. Some of the posters in Rafael's room of topless models were taken out of family albums from Moises' room.
The movie was shot in 4 weeks. The editing was done in 6 months. The postproduction lasted 12 months because covid got in the way.
The script was changed a lot during preproduction. The funding of the movie was secured with a totally different plot. The movie had a false preproduction in 2018, meaning that it was ready to be produced but cancelled midway through preproduction. The reason was that the director didn't think the script was good enough. He then hired 3 different screenwriters to help him fix the script, but none of it worked. He then changed the whole story and started a draft from scratch just 3 months before the actual shoot of the movie, in September 2019.
"Date Night" and "True Affection" from Father John Misty are played in the movie. Both songs are played from beginning to end. This is the second time in Salomon's career that a Father John Misty song is played in his movies, the other one was "Nancy From Now On" in the movie "Two Times You". All three songs are heard from beginning to end.