The actress voiced Dory, a Pacific Regal Blue Tang who suffers from short-term memory loss. Plot details for the new film are being held under wraps.
Andrew Stanton is directing the sequel from a script provided by Victoria Strouse. Lindsey Collins will be producing.
The original is the highest grossing film for Pixar, bringing in $868 million worldwide. It also won the Academy Award for Best Animated Feature.
Finding Nemo is returning to the big screen in 3D on September 14th.
Finding Dory comes to theaters June 17th, 2016 and stars Ellen DeGeneres, Albert Brooks, Diane Keaton, Eugene Levy, Ty Burrell, Willem Dafoe, Vicki Lewis, Idris Elba. The film is directed by Andrew Stanton.