Ellen DeGeneres tells PEOPLE she's "grateful" Pixar made Finding Dory, the sequel to 2003's Finding Nemo
Credit: Jason LaVeris/FilmMagic

Ellen DeGeneres, who voiced the beloved blue tang with short-term memory loss in Pixar’s 2003 blockbuster Finding Nemo, has been on a tireless campaign for the studio to make a sequel ever since.

On Friday at the D23 Expo in Anaheim, California, Disney Creative Chief Officer John Lasseter made a point of showing a reel of compiled clips of DeGeneres’s constant pleas. He then joked that he relented and gave in to the pressure. “OK, OK, OK,” he said. “We are in production on Finding Dory.”

DeGeneres, of course, took to the announcement like a fish in water.

“Well, it means a lot to me because it is a really sweet character,” DeGeneres tells PEOPLE of Dory, who in the new film will search for her family. “And she’s flawed, and I think that it’s important for kids to grow up and see flawed characters that are lovable and that really, no matter if they make mistake after mistake, they have a little surrounding pack, like a friendship with all these other fish that they travel with that forgive her. And even though they’re frustrated with her, they love her.”

Among the school Dory travels with are Albert Brooks, who returns to voice Marlin the clown fish, and new actor Hayden Rolence as Nemo, “because the original [actor Alexander Gould] is now 21 years old,” producer Lindsey Collins explained.

The underlying message of the new movie is that Dory is “lost,” DeGeneres says. “She’s been lost for a long time, and she’s just tried to act like everything’s fine. And in this film, you see that it’s kind of like she’s taken a little bit of a she’s paid a toll on it. She misses the fact that she has a family, and she realizes she has a family. And where are they? Did her parents give her away? Where is her family?”

Playing those parts will be Diane Keaton as Dory’s mom and Eugene Levy as her dad. Joining the cast will be new characters Hank, an octopus portrayed by Ed O’Neill ; Bailey, a beluga whale voiced by Ty Burrell ; and Destiny, a whale shark played by Kaitlin Olson.

RELATED VIDEO: Ellen DeGeneres on Life and Love

Burrell tells PEOPLE he signed on to do the film out of admiration for Pixar and the work of director Andrew Stanton.

WALL-E is one of my favorite films of all time, of any type, animated or not,” Burrell says, “so just being kind of asked to do something with Andrew Stanton was a big deal for me. And I’m also a fan of Finding Nemo. Pixar is just sort of – it just feels like a lot of animated film, the consistency of animated films is so high. And they’re so thorough. I really enjoyed viewing them because my experience is so far, including Mr. Peabody & Sherman, has just been so positive. And I just feel like the storytelling is so good, so thought-out. So they’re kind of a no-brainer for me. Plus, I’ve got two young kids.”

Speaking of the little ones, DeGeneres admits, “some of them are confused when I say I’m Dory because I’m supposed to be a fish. So they’re a little confused. So I don’t want to freak them out too much, but when they hear my voice, they know.”

Thinking more on it, DeGeneres adds, “So I think the kids who only knew the fish are now well, most of them are in college. We waited too long! But we have a fan base that will be like, really waiting for this film to come out. And all the new characters are fantastic. Ty Burrell is hilarious, and Ed O’Neill and Diane Keaton and Eugene Levy. It’s such a great cast. I really can’t wait for it to come out.”

Finding Dory dips into the summer movie pool on June 17, 2016.