Theodore Seville is the tritagonist of the Alvin and the Chipmunks film series. He is the youngest of the Chipmunks and the adoptive son of Dave Seville. His speaking voice is provided by Jesse McCartney and his singing voice is provided by Janice Karman. Most importantly, he is also shown to be good friends with Karai and her father Splinter. In Alvin and the Chipmunks: The Return of Queen Chrysalis, he, along with Simon Seville (Matthew Gray Gubler), Alvin Seville (Justin Long), Brittany Miller (Christina Applegate), Jeanette Miller (Anna Faris), and Eleanor Miller (Amy Poehler) replaces Twilight Sparkle (Tara Strong), Rainbow Dash (Ashleigh Ball), Fluttershy (Andrea Libman), Rarity (Tabitha St. Germain), Pinkie Pie, Applejack, and Spike (Cathy Weseluck) after they were kidnapped by Queen Chrysalis (Kathleen Barr).