RALPH FIENNES is ready to serve Batman.

    The Oscar-winning actor has signed on to voice Alfred Pennyworth, Bruce Wayne’s loyal butler, in “The Lego Batman Movie,” Warner Bros.’ spinoff of “The Lego Movie.”

    Fiennes now joins Will Arnett, who is reprising the Caped Crusader role he originated in “Lego Movie,” Michael Cera, voicing the hero’s sidekick, Robin, and Rosario Dawson, who is playing Batgirl. Zach Galifianakis is in negotiations to play the Joker.

    Alfred has been a Batman fixture since 1943.

    Chris McKay, the animation supervisor on “Lego Movie,” is directing the project, which has a script written by author-screenwriter Seth Grahame-Smith.

    Dan Lin, Roy Lee, Phil Lord and Christopher Miller, the custodians of the Lego screen brand, are producing.

    Fiennes, already part of the Warners family due to portraying Voldemort in the “Harry Potter” movies, returns as M in the new James Bond movie, “Spectre,” and will be seen in the Coen Bros.’s “Hail, Caesar!”

    “Lego Batman” will be his first movie voice work since the 2005 “Wallace & Gromit” feature, “The Curse of the Were-Rabbit.”(SD-Agencies)