Nope, this is real.
According to Deadline, Martin Scorsese is set to produce an origin film for The Joker. The Hangover‘s Todd Phillips will co write the script with 8 Mile‘s Scott Silver. Phillips is set to direct, as well as produce the film with Scorsese.
The film will be set under a new, unnamed banner Warner Bros is creating to expand their cinematic universe. According to the scuttlebutt, It won’t feature any current iteration of the character. While Jared Leto is still presumably set to play the Joker in the current crop of DC films, this one will be going with a different, younger actor.
And the reason for that is the setting. Supposedly, the film will be set in an early 80’s version of Gotham. As it’s meant to be a gritty origin story for the character, it’ll likely be much like Scorsese’s films from that period; Raging Bull, Taxi Driver, and the like.
My one suggestion? Don’t get another method actor to play The Joker. That all said, there’s no hard date attached to the film yet, so we won’t know more for a while.