The Joker's uniform has link to Heath Ledger's daughter in The Dark Knight

Heath Ledger set a new standard for comic book villains in The Dark Knight.

The 2008 blockbuster saw the Australian play the maniacal Joker, who sends Gotham into chaos as he takes on Batman, played by Christian Bale.

Sadly, however, in January of that year, Ledger died six months before the film landed in cinemas - though the world got the chance to see what he had done with the character.

He has since gone on to be lauded by critics and fans alike, and was awarded a posthumous Academy Award for Best Supporting Actor the following year.

But as well as his incredible performance, the Brokeback Mountain star left a special message for his young daughter.

During one of the stand-out moments in the movie, Ledger's Joker is seen visiting Harvey Dent at hospital after he's just had half his face blown off.

Warner Bros.

In order to sneak in, the master criminal steals a nurse's uniform and a red wig. I mean, you can hardly tell it's him.

If you looks a little closer, though, on his uniform you can see a name tag, which reads 'Matilda'.

That's the same name as his little girl, who was just a toddler at the time the film was made.

It's well known that Ledger's preparation for the role was incredibly intense, with him spending weeks creating the character.

One of Ledger's co-stars in The Dark Knight was Michael Jai White who played Gotham gangster Gambol.

And while their characters didn't get along in the film, White said he had the highest respect for Ledger as an actor.

White once spoke to ColliderLive about just how incredible it was to be acting in the same scene as Heath Ledger and how much dedication he had towards getting everything right.

Warner Bros.

The actor recalled a time Ledger went through hours of makeup to play his part, even though he wasn't on camera.

"He was so incredibly chill, the first day he comes in we shoot half of the day, he's in full makeup with cameras beside him, he's talking to the boardroom," White said.

"We break for lunch, I ask the director 'what are we shooting after lunch' and he says 'we're gonna finish up this side of the room'.

"I said, 'Do you mean to tell me Heath has been in hours of makeup and he's not gonna be on camera any time today', and he said, 'Yeah'."

"I was like wow, he just did that for us. That's for real and coming from the guy who played Spawn, hell no.

"No way would I do that. I would be in t-shirts and jeans if I don't have to be marinating in my own juices."