Ricardo Montalban's grandson, Alex Montalban, is the ardent fan/surfer dude who asks Hervé to "do the thing" in the hotel lobby near the end of the film.
In an interview with Stephen Colbert, Dinklage said kids in school used to tease him by saying Herve's trademark line from Fantasy Island "De plane! De plane!"
Director Sacha Gervasi once conducted a lengthy interview with Hervé Villechaize just prior to the latter's death. He found a fellow admirer in Peter Dinklage, and they worked together on a screenplay for several years before HBO greenlit the movie, with Dinklage starring and Gervasi directing.
Peter Dinklage is considerably taller than Hervé Villechaize. In reality, Villechaize was 3'11" while Dinklage is 4'5".
In 1957, Billy Barty founded the Little People of America organization to help people with dwarfism. In 2017, Mark Povinelli was elected President of that organization. In this film, Povinelli plays Barty.