The action star will be reprising his role of tree monster Groot not only in Guardians of the Galaxy Vol. 2, but also in blockbuster Marvel film Avengers: Infinity War.

Diesel confirmed the crossover project during a recent Facebook Live chat with fans, revealing, "Now, the Guardians will be included in Avengers: Infinity War and that’s incredibly exciting. You were told before everybody."

Reports of the Guardians possibly meeting up with the Avengers has been circulating for years, with Marvel boss Kevin Feige confirming a crossover would happen back in 2014, but he never revealed details of a timeline, and which film would be the setting for the epic meeting of heroes.

Fans will have to wait until May, 2018 for Avengers: Infinity War, but not as long for Guardians of the Galaxy Vol. 2, which hits cinemas in May (17).

In addition to Diesel, the rest of the Guardians, played by Chris Pratt, Bradley Cooper, Zoe Saldana, and Dave Bautista, will return for the highly-anticipated sequel.

Newcomers to the cast include Kurt Russell, who will play Pratt's onscreen father, as well as Sylvester Stallone, whose character details are being kept under wraps.

Director James Gunn teased the Rocky star's involvement in the film to during Comic-Con last month (Jul16), saying Stallone has a "very, very key, important role," adding, "It's not a huge role. He's a great and key supporting actor."

During the Marvel panel discussion, Gunn and Feige unveiled the first trailer for the follow-up, and the footage introduced the audience to Russell, while Stallone makes a brief appearance towards the end of the preview.