The trailer stars Margot Robbie (Harley Quinn/ Dr Harleen F Quinzel) dancing acrobatically in a cage, Cara Delevingne (Enchantress) submerging herself in black pond water and a bald Will Smith (Floyd Lawton/Deadshot) wielding a weapon.
The trailer fades out with The Joker’s ominous lines: “I’m not gonna kill you…I’m just gonna hurt you. Really, really bad.”
There has been a lot of controversy surrounding Leto’s portrayal of The Joker in recent weeks, with many criticising his tattooed look in the sneak peak fans were given earlier this year.
Suicide Squad will tell the story of a team of supervillains who take on dangerous black op missions for the government.
The super-villain movie also stars Viola Davis as Amanda Walker, Joel Kinnaman as Rick Flagg, Adewale Akinnuoye-Agbaje as Killer Croc, Scott Eastwood as Steve Trevor and Jai Courtney as Boomerang.
Warner Bros are set to release the movie in August 2016, less than six months after the release of Batman V Superman: Dawn of Justice in March next year.
The film is part of Warner Bros plans to roll out ten superhero and supervillain epics based on DC Comics characters by 2020.