Washington DC [US], April 10 (ANI): The trailer of the highly-anticipated film ‘Joker: Folie a Deux’ starring Joaquin Phoenix and Lady Gaga as Joker and Harley Quinn has finally been unveiled. Taking to Instagram, Lady Gaga treated fans with the trailer clip and captioned the post, which said, “Joker: Folie a Deux. Only in theaters October 4.” https://www.instagram.com/p/C5j8ik8xrHF/ Joaquin Phoenix will be playing the lead role in the film ‘Joker: Folie a Deux’. Lady Gaga will play the role of Harley Quinn opposite Joaquin Phoenix. The cast of the film includes Brendan Gleeson, Catherine Keen…