Leto shared the black and white fan-made photo on Instagram Monday, which features Nicholson's Joker standing over Ledger's rendition of the character with the caption "Don't worry, Leto will make us proud."
Leto is next in line to don the iconic clown makeup and green hair in next year's comic book adaptation of the Suicide Squad.
"Great work @gaunted! Was wondering who made it! Amazing. I see a few thought It was me but it wasn't. Just thought it was clever sweet + fun," the actor wrote on the photo sharing site giving recognition to the original photographer, Gaunted from Toronto.
In November, Suicide Squad producer Charles Roven detailed Leto's behavior during the filming of the movie which helped him get into character as the clown prince of crime. "It was different, it was fun," Roven said of the star's technique. "The group first wasn't sure because the [assistant directors] had to call him 'Mr. J' to get him to come to the set. And he did in many ways isolate himself from the rest of the group, but that's really what his character was."
"[It was] the purpose of his character in many ways, other than when he was with Harley [Quinn] or trying to get Harley," he added. "It was very entertaining, it was fuel for a lot of good sport and a lot of laughs and his isolation bonded the squad," Roven continued.
Suicide Squad opens in theaters Aug. 5, 2016.