JOAQUIN PHOENIX: (As Joker, singing) When you're smiling. MARTÍNEZ: Lady Gaga plays the Joker's accomplice, Harley Quinn. (SOUNDBITE OF FILM, "JOKER: FOLIE A DEUX") PHOENIX: (As Joker, singing) When ...

The Dark Knight of Gotham City. Batman, the brainchild of the millionaire Bruce Wayne, has worked to keep his hometown safe from the likes of the Joker, Penguin, Catwoman, and many others for decades.

The origin story of the "Joker" continues, as the sequel "Joker: Folie à Deux" hits theaters on Friday. Meanwhile on HBO, the origin story behind "The Penguin" is underway. JOAQUIN PHOENIX: (As Joker, ...

Batman's nemesis has returned to theaters in "Joker: Folie A Deux." And this time, he's got a song in his heart. (SOUNDBITE OF FILM, "JOKER: FOLIE A DEUX") JOAQUIN PHOENIX: (As Joker, singing) When ...