Will Poulter is set to play Adam Warlock in 'Guardians of the Galaxy Vol. 3'.

The 28-year-old actor has joined the cast of the eagerly-awaited Marvel movie, after his role was previously teased at the end of 'Guardians of the Galaxy Vol. 2'.

Will's character was first hinted at in a post-credit scene of the last movie, when Ayesha revealed the Sovereign she's created in a bid to destroy the Guardians.

Fans have subsequently speculated about the identity of the actor who would fill the role, and Will has now been cast in the film, according to Deadline.

Marvel is determined to ensure that specific details about the plot remain a closely-guarded secret, but production work is expected to begin in November, with James Gunn returning to direct the project.

The acclaimed filmmaker and other Marvel executives met with Will in August and decided that he was the ideal candidate for the role of Adam Warlock.

Earlier this year, James gave fans an insight into what to expect from 'Guardians of the Galaxy Vol. 3'.

The director explained that the upcoming movie - which will also star the likes of Chris Pratt, Karen Gillan and Zoe Saldana - will be "heavier" than the earlier films.

James - who helmed the two previous 'Guardians' movies - explained: "For 'Guardians 3', the script has basically been written for a long time. I've been playing with it in little ways over the years, but it's basically stayed the same since three years ago.

"It's pretty heavy actually. It's a heavier story, so it's an emotional process to go through."