Guardians of the Galaxy writer and director James Gunn has confirmed that the third instalment of his Marvel Cinematic Universe (MCU) trilogy will be part of 'Phase Four' of the sprawling series when it's released in 2020.

Gunn confirmed the news on Twitter during a string of conversations with fans online. The series is one of Marvel's most popular, having made a more than $1.5bn (£1.1bn) worldwide from the two films to date.

Asked simply if there was going to be a threequel, which was confirmed last year, Gunn said: "Coming in 2020."

The year of 2020 was the likeliest date for the anticipated sequel given Marvel's stacked slate of upcoming films, which runs through July 2019 with Jon Watts's sequel to Spider-Man: Homecoming.

Marvel Studios has three release dates pencilled in for movies in 2020, the first of which falls on 1 May 2020 – around the time that Marvel traditionally releases its biggest movies. Guardians 3 certainly fits the bill following Vol. 2's release in May 2017.

Marvel's remaining two films are set for 7 August and 6 November. Given what's coming up, one of these is likely to be a sequel to Doctor Strange. The other is up for debate and could see Marvel introduce a new hero.

As it stands Marvel has Black Panther set for release in February, Avengers: Infinity War coming up in April/May, Ant-Man and the Wasp in July, Captain Marvel in March 2019, the untitled Avengers sequel in April/May 2019 and Spider-Man 2 that July.

Guardians of the Galaxy Vol. 2 left a lot of potential areas to be explored in a possible sequel. Big-name actors appeared at the end as members of the Ravagers and the comics' original Guardians lineup.

Ving Rhames portrayed Charlie-27, Michelle Yeoh played Aleta Ogord, there was Michael Rosenbaum as Martinex and Miley Cyrus provided the voice of Mainframe. Their leader Stakar Ogord, was played by Sylvester Stallone.

One of the film's credits scenes also setup the introduction of Adam Warlock, which is certain to play a pivotal role in the future of the Marvel universe.

The Guardians themselves expand in the sequel, growing from the initial group of Star-Lord (Chris Pratt), Gamora (Zoe Saldana), Drax (Dave Bautista), Groot (Vin Diesel) and Rocket (Bradley Cooper) to also include Pom Klementieff as Mantis and, possibly, Karen Gillan as Nebula.

The Guardians will next appear in Avengers: Infinity War, marking their first crossover with the rest of the MCU. They're likely to be appear in its untitled sequel as well.