The first trailer for Joaquin Phoenix's 'Joker' is finally out, after months of sneak peek's being leaked on social media.

The Warner Bros. flick also stars Robert De Niro, 'Deadpool 2' star Zazie Beetz and 'GLOW' actor Marc Maron.

At the beginning of the trailer, Phoenix is seen talking to a psychiatrist who asks him:

“Does it help to have someone to talk to?”

He then replies: “My mom used to tell me to smile and put on a happy face,” he muses. “I thought my purpose was to bring laughter and joy to the world.”

Up until this point, the studios have shared very little about the movie

apart from a screen test of Phoenix in his Joker makeup and a brief snippet of filming.

'Joker' is slated for release Oct. 4.