The voice behind the cartoon characters

Often celebrities find some very weird characters to lend their voice to. Here’s a list of the best and strangest.

Katy Perry plays Smurfette opposite Neil Patrick Harris and Jayma Mays in The Smurfs, due out on July 29th. Perry's character channels Marilyn Monroe's famous Seven Year Itch moment in the movie's trailer, as the Smurfette's billowy white dress flies up over a windy grate.

Jennifer Aniston served as the voice for character Annie Hughes in 1999's Iron Giant, when the actress was still part of the Friends cast.

Anne Hathaway gave a voice to character Jewel in Rio. Though Hathaway made her singing debut in the film, she had done voiceover work before in shows The Simpsons and Family Guy.

Christina Applegate voiced sassy female chipmunk Brittany in Alvin and the Chipmunks: The Squeakquel alongside two other Chipettes, played by Amy Poehler and Anna Faris.

Ellen DeGeneres puckered up to play Dory in 2003's Finding Nemo. The comedian mastered the amnesiac fish's stumbling speech patterns in the film.

Emma Watson voiced the part of Princess Pea in The Tale of Despereaux. “I read the script, and I just loved it. It was so charming. I fell in love with Despereaux, so I really didn't have a choice. I had to be his princess,” Watson told MTV.

Isla Fisher gave voice to Dr. Mary Lou Larue in Horton Hears a Who! The Dr. Seuss-inspired film boasted a star-studded cast of Jim Carrey, Steve Carell, Seth Rogan and Jaime Pressly.

Jada Pinkett Smith played Gloria in Madagascar and Madagascar 2. "I always have such a good time with Gloria, it allows me to be very playful," Smith said of her role in the films.

Miley Cyrus provided the voice to Penny in Bolt. More than her voiceover, she won high praise for the song I Though I Lost You, which she sings in the film with John Travolta.

Nicole Kidman voiced penguin Norma Jean opposite Hugh Jackman and Robin Williams in 2006's Happy Feet.

Queen Latifah provided comedy as the voice of Ellie, a mammoth who is convinced that she is a possum, in Ice Age. "She has her own idea about who she is and she just won’t be dissuaded," the star said of her character.

Reese Witherspoon chose to play Susan Murphy a.k.a Ginormica in Monsters vs Aliens because the character had role model potential. "You always go for the great character to play, even if she's animated," Witherspoon said.