Jemaine Clement has joined the 'Avatar' franchise.

Jemaine Clement

Jemaine Clement

The 45-year-old comedian-and-actor is set to feature in the new instalment of James Cameron's sci-fi franchise as a marine biologist named Dr. Ian Garvin alongside other new cast members Kate Winslet, David Thewlis and Cliff Curtis.

Sam Worthington is set to reprise his role as Jake Sully in the upcoming sequels - the first of which will be released in 2020, followed by the other three in 20121, 2024 and 2025 - alongside Zoe Saldana as Neytiri, Giovanni Ribisi as Parker Selfridge, Stephen Lang playing Colonel Miles Quaritch and Sigourney Weaver as Dr. Grace Augustine.

Cameron said on the franchise's social media feeds: "I've loved Jemaine's work for years and I'm really pumped that he's joining our cast as Ian Garvin, one of my favourite characters."

The 64-year-old director previously teased that 'Avatar 2' will take place at least eight years after the first blockbuster, and sees characters Jake Sully and Neytiri have a "three-page argument" which is viewed from the perspective of their eight-year-old daughter, a sequence which is "critical" to the next film's plot.

Cameron said: "There's a three-page argument scene between Jake and Neytiri, a marital dispute, very, very critical to the storyline. I wound up shooting it all from the point of view of the eight-year-old hiding under the structure and peeking in."

The first movie focuses on the human led Resources Development Administration (RDA) attempting to mine alien moon Pandora for unobtanium, a hugely valuable mineral.

The moon is inhabited by the Na'vi, beings who appear primitive but are highly evolved, and as the planet's environment is poisonous to human beings, human/Na'vi hybrids called Avatars must link to human minds to allow for free movement on the planet.

Jake Sully, a paralysed former marine becomes mobile again through one such Avatar and falls in love with a Na'vi woman , however, he is drawn into a battle for the survival of her world when the RDA threaten to destroy it.