There was only one rehearsal before shooting. In multiple interviews, Timothée Chalamet and Armie Hammer said that director Luca Guadagnino asked them one day to come outside to do a rehearsal in the backyard of the villa. They walked to a patch of grass and flipped their scripts to a randomly selected scene to practice. When they opened the script, the page only read, "Elio and Oliver roll around in the grass making out." Chalamet and Hammer looked at each other and said, "Alright, let's go!" Just seconds into the making out scene, however, Guadagnino stepped in and directed them to act more "passionately." So they started making out and continued to do so, and no one told them to stop. Hammer said crew members had to pull them apart before the actors stopped, looked around and realized Guadagnino had just walked away, leaving them rolling around in the grass. This was their only rehearsal.
Despite various sexual scenes in the film, Armie Hammer stated in an interview that the most uncomfortable he ever felt during filming was when he was filming the dance scenes.
In an interview on Quotidien (2016), Timothée Chalamet revealed that Armie Hammer suffered wardrobe malfunctions from the shorts he wore throughout the movie, and his testicles had to be digitally edited out of some shots as a result.
Director Luca Guadagnino explained in an interview how he struggled with shooting the scene at the Piave Memorial, and he said it was Armie Hammer who finally suggested doing a one-shot.