Timothée Chalamet became reassured that Wonka wasn't "a cynical money grab" after he read the lyrics to the film's opening song.
In the new prequel movie, the Oscar-nominated actor plays a young version of Roald Dahl's classic chocolate inventor Willy Wonka.
While he felt sceptical about the project at first, he became convinced it wasn't a cash grab after reading the first few pages of the script.
"Like many people, when there are remakes, I feel very protective over the original character and versions you love," Chalamet told GamesRadar+. "Your eyebrows go up with scepticism about (whether) this is a legitimate, worthwhile story or a cynical money grab.
"But I was reading the first three pages of the script, and the song Hat Full of Dreams was in there. And there was no music to accompany it, but the lyrics were so clever."
From reading the song's lyrics, Chalamet realised that his Wonka was very different to the character played by Gene Wilder in 1971's Willy Wonka & the Chocolate Factory and Johnny Depp in 2005's Charlie and the Chocolate Factory.
"(It's) about this young Willy, who was definitively not the crazy, cynical, kind of jaded, brain-fried version that we see in the two prior films but was very hopeful, young, ambitious, won't-take-no-for-an-answer, maybe a little naïve," he shared.
Wonka marks the first time the 27-year-old can be seen singing and dancing on-screen. While he wasn't actively on the lookout for a musical role, he couldn't resist Wonka when it came along.
"I love musical theatre and I love song and dance," he said. "And I love old Fred Astaire movies and the original Charlie and the Chocolate Factory with Gene Wilder. I didn't think I'd get a chance to do it, not like this. But Paul King is one of these directors that you don't say no to."
Wonka will be released in U.K. cinemas on 8 December and U.S. theatres on 15 December.