Nicolas Cage thought Javi was the best written character in the movie, so much so he even asked to trade parts, as he thought playing his own biggest fan was more meta than playing himself. It wasn't until Pedro Pascal was cast that Cage eventually relented.
A sequence involving Nicolas Cage reprising some of his most iconic roles like Volte/face (1997), Les Ailes de l'enfer (1997), Leaving Las Vegas (1995) and 60 secondes chrono (2000), in a long black-and-white fight sequence between him and his younger self in a Surrealist German Expressionist set evoking of Le Cabinet du docteur Caligari (1920), was cut from the film as the studio thought it didn't fit the third act. According to Cage, the deleted scene will be released on home media.
According to Neil Patrick Harris, Nicolas Cage had body makeup to cover his tattoos. When he asked Cage why Nick Cage the character doesn't have the tattoos Nicolas Cage the real person has, Cage said the character didn't have as many wives as him.
At the end of principal photography, the whole cast was gifted a pillow with Nicolas Cage's face on it - each one autographed by him.
Nicolas Cage said in an interview that he probably will never watch the movie because "the idea of going meta and playing a quote-unquote surrealistic version of myself and a quote-unquote surrealistic version or interpretation of a younger version of myself going head to head might just be too psychologically invasive for one Nicolas Cage.... I will go to the premiere, but I'm probably not going to be sitting in the audience." However, due to a conflict between the director and the studio, Cage had to watch the movie to decide whether some scenes should be cut or not.