It was a lot of fun talking with Peter and Lou at the Ratatouille premiere on June 22nd, 2007.
Prior to this movie, they were both artists/animators at Pixar, not professional voice actors. As often happens with animated films, they provided voices for characters during the animation process (also known as scratch voices). Sometimes filmmakers like those voices so much, they decide to keep them, thus launching new careers for their animators.
While Lou left to work at LAIKA, Peter stuck around at Pixar and was the inspiration for the character of Russell in Up. He also started directing films. His latest is Elemental. We hope, now that he’s a big-time director, that his diet has improved!