The Joker is one of the most iconic and popular villains in history. And we're not just referring to the history of comic books when we say that - Batman's arch-enemy stands up alongside the likes of Professor Moriarty, Darth Vader, The Wicked Witch of the West, Cruella de Vil and the Devil himself as one of the most recognizable bad guys in fiction.
As a result of his popularity, there have been countless adaptations of the character across various media platforms. As well as appearing in comic books and graphic novels, The Joker has appeared on television, in movies, in video games and on all manner of merchandise and paraphernalia.
In 1989, the man who was clearly born to play The Joker took on the role of the character - and he did so brilliantly. That man was, of course, Jack Nicholson, and he made his one and only appearance as the character in Tim Burton's Batman. The Joker had appeared on the small screen in numerous animated series since Romero's version had last been seen, but this live action, big screen return was long overdue.
Nicholson's Joker still possessed an element of campness - you could clearly see the influence of Cesar Romero - but Burton and Nicholson took the character down a much darker route.
This version was violent and temperamental and, even when he was being light and funny, those moments would be juxtaposed with acts of physical brutality. In the same vein, his bright purple suit and constant sickly smile were in stark contrast to the drab and very grey version of Gotham City created by Burton for this movie - something that gave the character an edge and made him even more unsettling.
His line "have you ever danced with the devil by the pale moonlight" has become one of the most iconic in cinema history and defines Nicholson's interpretation brilliantly. Many still argue that this version is the definitive Joker, but that's simply a matter of opinion.
The Dark Knight Trilogy was a huge success. Christopher Nolan brought a level of gritty realism to the world of Batman that had never been attempted before with Batman Begins, The Dark Knight and The Dark Knight Rises between 2005 and 2012. But the highlight of the trilogy was undoubtedly the late Heath Ledger's portrayal of The Joker.
His sole appearance came in The Dark Knight, in which he was depicted as a sociopath and a bringer of pure chaos. He was completely reimagined and his appearance was far more rugged and shabby than that of any version of the character seen before and, frankly, he was the darkest, most unpredictable and most violent version as well.
To prepare for the role, Ledger reportedly locked himself away in a hotel room for weeks; perfecting his mannerisms, totally immersing himself in the character. Some people have theorised that getting inside the head of such a maniacal character contributed to Ledger's suicide, but that is, of course, just a theory.
Ledger's passing came just before the release of The Dark Knight in 2008, but he received universal praise for his performance and even earned a posthumous Academy Award for Best Supporting Actor for it. His iconic line "why so serious" will forever live on in cinematic lore.
Next in line to play The Joker on the big screen is Jared Leto - a man who will put as much into the role as Ledger did back in 2008 (he's already terrified his fellow cast members by remaining in character at all times on set - and he's famously sent them some very strange gifts, including bullets and dead animals).
Leto has the responsibility of taking on the role in the DC Extended Universe, starting with 2016's Suicide Squad and, potentially, in several other movies going forward in the franchise .
This version looks more different to any that came before it than any other version, with his slicked back green hair, silver teeth and body covered in tattoos. He looks as though he revels in the pain of other more than other versions, and fans and critics are completely divided about him, based on what they've seen of him in promotional material and trailers so far, with some claiming it looks as though Leto and the people behind Suicide Squad are "trying too hard to be different".
It remains to be seen how he will be received once Suicide Squad is actually released, but the likes of Jack Nicholson and Heath Ledger are undoubtedly tough acts to follow, and Leto will need to have brought his A-game to his performance in order to garner favourable reviews. All we can say is that we remain hopeful of this drastically different version being as brilliant as his predecessors.