Warning: the following contains spoilers about Johnny Depp's upcoming role in Fantastic Beasts and its sequel.
A week after it was announced that Johnny Depp was joining the sequel to the upcoming Fantastic Beasts and Where to Find Them, his mysterious role has been revealed.
The film's director, David Yates, broke the news that Depp will be taking on the part of Gellert Grindelwald during an interview with The Leaky Cauldron on Tuesday. As previously reported, Depp will have a cameo in the first installment of the Fantastic Beasts franchise, hitting theaters Nov. 18.
WATCH: J.K. Rowling Announces There Will Be a Total of Five ‘Fantastic Beasts and Where to Find Them’ Films
"The whole principle of casting the movie was go with the best actor. Go for the most inspired, interesting, right fit for that character. And as we approached Grindelwald we thought, 'Who's going to take this in an interesting direction?'" Yates said.
As fans of the books will remember, Grindelwald (played by Jamie Campbell Bower in flashbacks of Harry Potter and the Deathly Hallows) was considered to be one of the most dangerous dark wizards of all time, stealing the Elder Wand and creating a murderous army before being defeated by Albus Dumbledore in a duel in 1945 and imprisoned in his own fortress.
Grindelwald was killed by Voldemort in 1998 after refusing to give up information on the Elder Wand. The character was also a former love interest of Dumbledore, before killing Dumbledore's sister, Ariana.
RELATED: Muggles Rejoice! Dumbledore Will Appear in the ‘Fantastic Beasts And Where To Find Them’ Movies
"We were excited about seeing what he would do with this guy, the character. He's fearless; he's imaginative; he's ambitious," Yates continued. "We thought he would do something fun and special. So we went for him, purely on that selfish basis. We don’t care if he’s famous or not famous. We just know he's interesting."
ET caught up with the Fantastic Beasts cast at the film's junket on Saturday, where it seems Depp's role was a secret even to them.
"I found out when the world found out," Katherine Waterston revealed. "If you're not in a scene with someone you don't know… I think I was the last to know that Johnny Depp was in the movie. Eddie [Redmayne] knows a little bit more than the rest of us."
"I did know when we came to shoot that moment," Redmayne agreed.
EXCLUSIVE: Eddie Redmayne Opens Up About Fatherhood: ‘I Don’t Think Anything Can Prepare You’
"I didn't get to work with him, so it was something that existed completely separate from me," Colin Farrell said. "I never had any scenes with him, so yeah, I think he came in way after I had finished."
While it's unclear whether Alison Sudol worked with Depp on-set of the first film, she couldn't contain her excitement over his addition to the cast.
"All of this is so surreal," she shared. "It's like one surreal moment after the next, and then to get to work with Johnny Depp -- he's just a legendary actor and so incredible and creates these amazing characters. So the fact that we get to be in a film with him -- we're not even sure what's going to happen in the next one -- but the fact that he's going to be in it at all [is amazing]."
WATCH: JK Rowling Reveals Official Cover of 'Fantastic Beasts and Where to Find Them' Published Screenplay
See more on Depp's upcoming Fantastic Beasts cameo in the video below.