Oh no, what has Jared Leto done to himself?

The screen idol is almost as famous for his long, flowing locks as he is for his remarkable acting, but he has never left any doubt about his commitment to each part he plays.

His transformation for his most recent role as the transsexual drug addict Rayon in Dallas Buyers Club earned him a Best Supporting Actor Oscar last year and reconfirmed him as one of his generation's biggest talents.

How on earth could he possibly top that? 

It looks like he is going to give it a good go as he takes on a psychotic, murderous genius with green hair and a red, slashed mouth?

Following in the footsteps of Heath Ledger and Jack Nicholson, Leto's latest high-profile role is The Joker in the upcoming all-star DC Comics adapation Suicide Squad.

The actor already chopped his luxurious locks earlier this year and now he is preparing for the next stage.

Fans were sent into a frenzy when he recently posted a picture in Instagram with the caption: “Transformation begins.”

His remarkably pale skin has set fans wondering whether he will keep it natural or use white make-up to create The Joker’s iconic look.

His shorn, bleached hair indicates that he is preparing to dramatically dye it bright green.

Even so, he will still have to go a long way to match the visual and performance extremes of Heath Ledger who famously played the character in 2008’s The Dark Knight.

Suicide Squad will be the third film in the DC comics shared universe series after 2013’s Man of Steel and next year’s Batman vs Superman: Dawn of Justice, where Henry Cavill's Caped Crusader will face off against Ben Aflleck's Batman.

The Suicide Squad will follow on from that story, introducing a league of supervillains allowed to operate for the government on shady covert missions in lieu of prison time.