Ellen DeGeneres (left) provides the cheerful voice of the eternally optimistic blue tang Dory. She was directed by Andrew Stanton (right). (Photo Courtesy Disney Enterprises, Inc./Pixar Animation Studios)

Most Hollywood sets are abuzz with the sounds of actors delivering their lines under the glare of dozens of cameras and lights. Not so at Pixar Animation Studios, home to the cast of Finding Nemo.

"The actors are standing alone in a recording studio with just a microphone," says Andrew Stanton, the director of Finding Nemo. "There is no set. There are no costumes. There are no other actors. They are left with just their imagination."

That's just fine with Alexander Gould, who plays Nemo. He says he prefers acting in animated films rather than hamming it up for the camera in feature films.

"It was a lot easier because you don't have to worry about the wardrobe or the props," says the 9-year-old actor from California. "You just come in, and the lines are loud, and they're fast, and you just do it."

Getting into character isn't always a cinch, especially when actors must invent each scene in their own minds. Fortunately, Stanton was there to help.

"My role was to describe what the scene was, what the character was doing in the scene, what other characters were around them, and if they had to talk loudly or softly," he says.

In the end, the film's actors had to act out every emotion in the book. Because the movie features lots of chase scenes, they were often called upon to act scared and talk quickly. Stanton's character, Crush the turtle, demanded a whole different set of emotions.

"A lot of times, you aren't thinking about what species you're playing," says Stanton. "It's more about what kind of character you are. Crush was very mellow and acted like a surfer, so I had to sound very southern California. Nothing phased him, so that's what I had to think about."

As for Ellen DeGeneres, the voice behind the lovable, but forgetful Dory, she had to play up her character's sunny personality.

"I played the character of Dory almost like she was a 7-year-old," says DeGeneres. "She's so naive and childlike, which is a beautiful thing because she never expects anything bad or dangerous to happen. She's happy all the time and very positive."

Besides DeGeneres, there are many other famous voices behind Nemo's aquatic cast. The West Wing's Allison Janney plays Peach the starfish, and Everybody Loves Raymond's Brad Garrett takes on the role of Bloat the blowfish.

After all those hours in the studio, Alexander Gould says it was both exciting and strange to finally see the movie on the big screen.

"It was really weird when I heard my voice coming out of a fish," he says.