Wonka director Paul King has claimed that Timothee Chalamet has "a beautiful singing voice" in the upcoming film.

The movie serves as a prequel to the 1971 classic Willy Wonka and the Chocolate Factory - an adaptation of a Roald Dahl novel - and follows Chalamet's Willy Wonka from his young entrepreneurial days through to his destiny as an eccentric chocolate mogul.

The film is not a musical but does feature several musical numbers from Chalamet, whom King compares to the legendary Bing Crosby.

"[He]'s got a beautiful singing voice," King told Total Film.

"The person it reminded me of was Bing Crosby. There's quite a range, because it does go from a couple of bigger, showstopper-y sort of things, to moments of real, pure emotion and he can do it all... I'm going to sound like a crazed fan."

Wonka is due for release on December 15.