Robert Pattinson revealed while auditioning for the role, he sneakily took a selfie in the batsuit as a memento "just in case it didn't work out."
Colin Farrell stated that he went to Starbucks on the WB lot to try out his prosthetics and makeup for the Penguin for the first time. Nobody recognized him, but he got a couple of stares from people.
This is the first version of Batman to address the black eye makeup under the cowl directly. In previous films, the makeup just disappeared when Bruce took his mask off. Matt Reeves stated, "I just loved the idea of taking off [the mask] and under that, there's the sweating and the dripping and the whole theatricality of becoming this character."
Robert Pattinson's audition/screentest took place while he was in rehearsals for shooting Tenet (2020) in Los Angeles in May 2019. Pattinson had to lie to Christopher Nolan about it, but Nolan, who was no stranger to Batman and Warner Bros., immediately figured it out. Pattinson: "I said I had a family emergency. And as soon as I said it, he goes: 'You're doing the Batman audition, aren't you?'" When Pattinson was told that he won the role of Batman a day before principal photography for Tenet began, he was surprised that Nolan also knew and congratulated him, although Pattinson hadn't told anybody about it yet.
Matt Reeves stated that his version of the Riddler was partly inspired by the infamous Zodiac Killer, an unidentified serial killer who operated in northern California in the late 1960s. The Zodiac used ciphers in his infamous letters to the police, which made Reeves call him a "real-life" Riddler. In the film, Riddler begins his video saying, "This is the Riddler speaking," and the Zodiac began his letters with "This is the Zodiac speaking." The Zodiac also murdered his victims while wearing a leather suit and mask with glasses over the mask, just like the Riddler wears.
Matt Reeves: [The Godfather (1972)] Reeves stated that Colin Farrell's Penguin takes inspiration from the character Fredo (John Cazale) in relation to the fact that both characters are underestimated by others but have huge potential.