New The LEGO Batman Movie poster arrives In honor of Batman Day, Warner Bros. Pictures has released a new The LEGO Batman Movie poster, featuring the titular hero and a new tagline for The LEGO Movie spin-off. Check it out in the gallery below. Will Arnett reprises his role of Batman from The LEGO Movie as the voice of the titular Dark Knight, alongside Michael Cera as Robin the boy wonder, Rosario Dawson as Batgirl, Ralph Fiennes as Alfred Pennyworth, Mariah Carey as Gotham’s mayor and Zach Galifianakis as The Joker. In the irreverent spirit of fun that made The LEGO Movie a worldwide phenomenon, the self-described leading man of that ensemble – LEGO Batman – stars in his own big-screen adventure: The LEGO Batman Movie.