Amandla Stenberg has joined the cast of 'Dear Evan Hansen'.

The 21-year-old actress-and-singer has signed up for the film adaptation of the Broadway show and will be singing in the movie.

Amandla, whose previous credits include 'The Hate U Give' and 'Everything, Everything', will play the role of Alana Beck - a senior high school student who masks a deep loneliness and isolation with her cheery demeanour and social media savvy.

The part has been expanded for the movie as Stenberg will perform a new song composed for the project. Amandla is writing the tune with lyricists Benj Pasek and Justin Paul, who wrote the music for the stage show.

Broadway star Ben Platt is set to play reprise his role as Evan as the project moves to the big screen, while Kaitlyn Dever has been cast as the female lead.

The 23-year-old actress will play the role of Zoe, the tragic classmate's sister, who begins dating Evan after he strikes up a relationship with the boy's family.

The plot follows Evan Hansen, a teenager with social anxiety who gets caught up in a lie when the family of a classmate who committed suicide confuses one of Evan's letters for his suicide note.

Stephen Chbosky is directing from a script written by Steve Levenson, who penned the book for the stage musical. Marc Platt and Adam Siegel are producing the flick.

The musical has received critical acclaim since it premiered in 2015 and won five Tony Awards at the 2017 ceremony.