Chris Columbus, the director of the Harry Potter films, says that Robin Williams wanted to play Professor Lupin. Columbus directed the first two Harry Potter films, titled The Sorcerer’s Stone and The Chamber of Secrets, based on J.K. Rowling’s books as its source material. The beloved blockbuster trilogy that followed the Golden Trio of Harry Potter (Daniel Radcliffe), Hermione Granger (Emma Watson), and Ron Weasley (Rupert Grint) went on to generate billions of dollars at the box office, placing it behind the MCU and Star Wars as the third-highest-grossing series.

To commemorate the 20th anniversary of Harry Potter and the Philosopher’s Stone, Columbus chatted with Total Film. On November 16, 2001, the film — the first big-screen version of the Harry Potter book series – was released in the United Kingdom and the United States.

Robin Williams showed interest in playing Lupin, a werewolf who first appears in Harry Potter and the Prisoner of Azkaban, the third book and film in the series, according to Columbus.

According to Total Film, Williams was passed up for the part because casting him would have violated a guideline prohibiting the employment of any American performers in order to “maintain a degree of authenticity.”

“I had a conversation with Robin Williams, who wanted to play Lupin. It was very difficult for me to say ‘It’s all British. There’s nothing I can do.'”

Robin Williams, a huge fan of the novels, approached Chris Columbus in 2000 about portraying Hagrid, a part that was later filled by Robbie Coltrane. Williams and Columbus had previously worked together on Mrs. Doubtfire, Nine Months, and Bicentennial Man. Unfortunately, Columbus had to reject him owing to Rowling’s directive that they must only hire British actors from the top down.

In a 2016 interview with HuffPost, casting director Janet Hirshenson referenced the British actors rule, telling the site a similar anecdote regarding Williams’ aspirations to join the franchise. She stated that he had been passed over for the part of Hagrid.

“Robin [Williams] had called [Chris Columbus] because he really wanted to be in the movie, but it was a British-only edict, and once he said no to Robin, he wasn’t going to say yes to anybody else, that’s for sure,” she remarked at the time. “It couldn’t be.”

David Thewlis, who first appeared in Harry Potter and the Prisoner of Azkaban, was cast as Professor Lupin. Harry Potter and the Order of the Phoenix, Harry Potter and the Half-Blood Prince, and Harry Potter and the Deathly Hallows Part I & II saw Thewlis reprise the role. Although I admire David Thewlis’ performance, it’s difficult not to fantasize about what may have been if Robin Williams had been cast in the role.

Williams didn’t specify which characters he was interested in in a 2001 interview with The New York Post, but said of his ambition to join the franchise: “There were a couple of parts I would have wanted to play, but there was a ban on [using] American actors. Maybe one day. Say if [Harry] goes to Yale and becomes president.”

The third installment, Harry Potter and the Prisoner of Azkaban, was directed by Alfonso Cuarón.

The fourth film, Harry Potter and the Goblet of Fire, was directed by Mike Newell, and the remaining four films were directed by David Yates: Harry Potter and the Order of the Phoenix, Harry Potter and the Half-Blood Prince, Harry Potter and the Deathly Hallows – Part 1, and Harry Potter and the Deathly Hallows – Part 2.

In a 2016 interview with HuffPost, casting director Janet Hirshenson referenced the British actors rule, telling the site a similar anecdote regarding Williams’ aspirations to join the franchise. She said he was passed over for the part of Hagrid, which was eventually given to Robbie Coltrane.

“Robin [Williams] had called [Chris Columbus] because he really wanted to be in the movie, but it was a British-only edict, and once he said no to Robin, he wasn’t going to say yes to anybody else, that’s for sure,” she remarked at the time. “It couldn’t be.”

Despite the fact that the Harry Potter series has come to an end, the Wizarding World continues with the Fantastic Beasts series. Fantastic Beasts: The Secrets of Dumbledore, the next installment in the series, will be released on April 15, 2022. “With Grindelwald’s power rapidly growing, Albus Dumbledore entrusts Newt Scamander and his friends on a mission that will lead to a clash with Grindelwald’s army, and will lead Dumbledore to ponder how long he will stay on the sidelines in the approaching war,” reads the official synopsis.