Gunn, best known for directing the "Guardians of the Galaxy" series for Marvel Studios, took to Twitter on Friday to share the names of 24 actors who will be starring in the much-anticipated film.
"Don't get too attached. #TheSuicideSquad" he wrote along with a list of the cast members.
Margot Robbie will return as Harley Quinn, Viola Davis as Squad mastermind Amanda Waller, Jai Courtney as Captain Boomerang, and Joel Kinnaman as Rick Flag.
They will be joined by an equally impressive list of newcomers -- Idris Elba, John Cena, Nathan Fillion, Peter Capaldi, David Dastmalchian, Taika Waititi and Pete Davidson.
The project will also mark Gunn's reunion with his "Guardian of the Galaxy" stars Michael Rooker and Sean Gunn, who is also his brother.
Daniela Melchior, Joaquin Cosio, Flula Borg, Mayling Ng, Storm Reid, Steve Agee, Alice Braga, Juan Diego Botto, Julio Ruiz, Tinashe Kajese and Jennifer Holland round out the cast.
Gunn and Warner Bros have not yet revealed the characters details of the new cast members.
"The Suicide Squad" is being branded as a relaunch and the studio had roped in Gunn earlier this year. He has also penned the script.
The 2016 movie, directed by David Ayer and featuring the likes of Will Smith, Robbie and Davis, was met with poor reviews upon its debut. But the film was still able to make a splash at the global box office, raking in over USD 746 million.
"The Suicide Squad" will be produced by Chuck Roven and Peter Safran, while Nik Korda will serve as executive producer. Shooting will start later this month and the film will release in August 2021.