While the Robin looks a lot like the Carrie Kelley version, apparently it's not as the character is voiced by Michael Cera. Joker is voiced by Zach Galifianakis (via USA Today).
"The Joker sees himself on the same level as Batman, a peer, at the top of the game," director
"Robin is a super-positive kid who always sees the glass as half full. Really, at the end of the day, he just wants a hug," McKay says. "Michael brings the sweetness and honesty."
Lego Batman hits February 10, 2017 also starring Will Arnett as Batman, Ralph Fiennes as Alfred, Rosario Dawson as Batgirl, and Mariah Carey as Mayor Marion Grange.