With production scheduled to begin next month, the cast of 20th Century Fox's Wolverine 3 is growing larger and larger. Today we have word that British actors Stephen Merchant and Richard E. Grant have joined the sequel, alongside Hugh Jackman, Patrick Stewart and Boyd Holbrook, who is playing the main villain. No details were given for Stephen Merchant's character, but Richard E. Grant is said to be playing a villainous mad scientist.

Deadline reports that more actors are in various stages of negotiations for the superhero adventure, although no specific names were mentioned, or what characters they may be playing. Wolverine 3 will be Hugh Jackman's final performance as Logan, bringing a 17-year run as the beloved mutant to an end, spanning nine movies. It isn't known if Stephen Merchant and Richard E. Grant's characters are based in the Marvel Comics, or if they were created specifically for this movie.

Last week, a new casting call hinted that Wolverine 3 is looking for an actress to play fan favorite mutant X-23, although that character still has not been confirmed yet. X-23, a.k.a. Laura Kinney, was created by Craig Kyle for the animated TV series X-Men: Evolution, making her debut on the show in 2004. She soon transferred over to the comics, where she was further created by both Craig Kyle and Christopher Yost, who went on to write the scripts for Thor and Thor: The Dark World. X-23 was cloned from Wolverine's DNA, and her name comes from the fact that she was the 23rd attempt at creating a clone, and by far the most successful. Much like Wolverine himself, X-23 has regenerative healing abilities and retractable adamantium claws, along with superhuman strength, speed, agility, reflexes and heightened senses.

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James Mangold (The Wolverine) is directing from a script by David James Kelly, with Lauren Shuler Donner producing. 20th Century Fox has already set a March 3, 2017 release date for Wolverine 3, which doesn't have any direct competition at the box office yet, although it will open one week before Warner Bros.' Kong: Skull Island and 20th Century Fox's The Boss Baby. Before Wolverine 3 hits theaters, though, fans will be able to see Hugh Jackman in X-Men: Apocalypse next month, since his appearance was teased in a trailer that dropped this week.

Stephen Merchant is best known for co-creating the original U.K. version of The Office with Ricky Gervais. He most recently voiced roles on The Simpsons and American Dad, while appearing in a three-episode arc on The Big Bang Theory. Richard E. Grant most recently starred in USA Network's Dig and the U.K. series Jekyl & Hyde. We'll keep you posted with more casting updates as we get closer to production starting on Wolverine 3.