Taking to Instagram, Chalamet, 25, shared a photo of himself on the Wonka set, wearing a burgundy velvet jacket, patterned scarf and brown top hat, a classic look for the character.
"The suspense is terrible, I hope it will last," Chalamet captioned the picture.
Chalamet's take on the role will be an origin story for the character created by Roald Dahl in the 1964 children's book Charlie and the Chocolate Factory.
The actor will show off his singing and dancing skills in the musical fantasy film.
This is not the first time Dahl's famous character has been given the movie treatment. The novel was first adapted in 1971 and starred Gene Wilder as the title character in Willy Wonka & the Chocolate Factory. In 2005, Johnny Depp took on the part in Charlie and the Chocolate Factory, directed by Tim Burton.
The new take recounts Willy Wonka's early years and will be the first time the five children who win golden tickets – Charlie Bucket, Augustus Gloop, Veruca Salt, Violet Beauregarde and Mike Teavee – will not feature in the story.
Wonka is directed by Paul King (Paddington 1 & 2), who co-wrote the film with Simon Farnaby (Paddington 2, Mindhorn) and Simon Rich (Inside Out, Saturday Night Live). The film has an impressive comedy cast, featuring Olivia Colman, Rakhee Thakrar, Paterson Joseph, Keegan-Michael Key, Rowan Atkinson, Sally Hawkins, Matt Lucas and Rich Fulcher.
'Wonka' is set for release in 2023