Joaquin Phoenix is currently preparing to star in forthcoming movie Joker - but with Heath Ledger's arguably definitive performance as Batman's nemesis still looming large in the memory, you'll probably find yourself considering all the other actors to play the role.
The 'Clown Prince of Crime' may have seemed a nightmarish character when you watched the movies as a kid, but it seems the role itself comes with its own demons.
From the days of Cesar Romero taking on the Caped Crusader, to the more recent appearance of Jared Leto in Suicide Squad, reports suggest there isn't a single actor who's taken on the infamous role and managed to escaped without lasting remnants of the creepy character.
Back in the 60s Adam West played the suave millionaire Bruce Wayne taking on all sorts of bad guys with Robin the Boy Wonder in a colourfully camp take on the character.
One of these bad guys was Cesar Romero's Joker.
Romero embraced the show's cartoonish elements, making the first live-action incarnation of the character more of an impish pantomime villain than the darkly sinister incarnations to come - in contrast to the 'Latin lover' roles he was used to picking up for the big screen.
However, he refused to shave his moustache, with make-up teams left to try in vain to cover it up. It added something to the ridiculousness of the character - his dark stubble clearly visible through the layers of white facepaint - but while he played many roles that he would take much more seriously across a 50-year screen career, for many it was this throwaway performance that defined his acting legacy.
If someone said Mark Hamill, you'd most likely think of Star Wars' legendary Jedi, Luke Skywalker - which, to be fair, is almost certainly probably the actor's biggest role.
But after he hung up his cloak and light saber he delved into the world of voiceovers and would soon become the voice of the Joker in the 90s cartoon Batman: The Animated Series.
He admitted that he never thought he'd get the job, but it ended up having a huge impact on his career-to the point where voice work has dominated his IMDb page over the last couple of decades.
But it seems the role seeps into everyone - describing himself as a 'real comic book nerd', he's admitted to becoming extremely protective over the role, telling IGN in 2010: "I'd rather not let anyone else sleep in my sleeping bag." Eek.
One-time Hollywood hellraiser Nicholson may not have been the first actor to play the Clown Prince of Crime, but his turn in Tim Burton's 1989 movie reinvented the Joker as a menacingly malevolent figure, making it one of the most memorable performances yet.
Nicholson's take on the Joker edged closer than anyone else had dared to the remorseless serial killer originally envisioned by creators Bill Finger, Bob Kane, and Jerry Robinson.
So how did the role haunt him? Well, ok, he's never been on record to indicate as much, and in any case he's scarcely unused to playing troubled, troubling or downright psychopathic characters.
However, when Heath Ledger died, Nicholson was documented by reporters as having commented, simply: "Well, I warned him." Now, some dispute this quote and claim he actually said 'I warned 'em', which is also cryptic.
Still, it's difficult not to see the character as having had an impact on the veteran actor, especially since he told MTV in 2007: "The Joker comes from my childhood. That's how I got involved with it in the first place. It's a part I always thought I should play."
Jared Leto is the most recent actor to take on the role of the Joker when he featured in the 2016 film Suicide Squad - and to be fair Leto's character was probably the best thing in the movie.
Leto went to great lengths to get into the mind of the criminal clown and admitted he found the role very challenging.
He remained in character for most of the shoot, spending most of his time alone. Leto even went so far as to send a rat to Margot Robbie and a dead pig to the rest of the cast, as well as other... let's say interesting gifts.
Acts befitting the character himself, you might say - it's enough to make you fear for the well-being of someone who feels they need to absorb the Joker's character IRL in order to play the role.
But you knew where this piece would end. Heath Ledger delivered a career-defining performance as the Joker in Christopher Nolan's The Dark Knight, released in 2008, but tragically it would prove to be his last.
To prepare for the part, in addition to studying darker comic depictions of the murderous villain, the works of Francis Bacon, and both the film and novel A Clockwork Orange, Ledger prepared torturously for the role as part of his commitment to the 'method' school of acting, documenting his experiences in what he referred to as a 'Joker journal'.
Working on the character sent his mind racing as he holed himself up in his apartment, leading to him sleeping for little more than two hours a night.
The medication he sought to combat this ultimately contributed to his life being tragically cut short, as he overdosed on a combination of sleeping pills, prescription painkillers and anti-anxiety meds in January 2008. He was just 28 years old.
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