Director Todd Phillips said he wants comic book movie fans to know that there is no chance of Joaquin Phoenix’s Joker and Robert Pattinson’s Batman ever crossing over on the big screen. He added that doesn’t mean Pattinson won’t ever possibly face off against Joker, it just won’t be his version.
This is the "official" time, the "carnival-crazies" take over. Since it is a classical carnival costume to be dressed as a clown, I don't see "a coincidence" here.