"It's official," DeGeneres tweeted alongside a poster for the anticipated followup, "Finding Dory."
DeGeneres lent her voice to the animated regal tang in the 2003 film and is set to reprise her role.
No other information was mentioned in the tweet.
"Finding Nemo" was about overprotective clownfish Marlin, played by Albert Brooks, who enlists the help of DeGeneres' confused Dory to help him find his young son, Nemo, played by Alexander Gould, who was scooped up by a snorkeling dentist and place in his fish tank.
Brooks was previously announced as being involved in the movie, which is set for release in 2015.