Alvin and the Chipmunks: The Squeakquel is a 2009 American live-action/animated jukebox musical comedy film directed by Betty Thomas and written by Jon Vitti and the writing team of Jonathan Aibel and Glenn Berger, based on the characters Alvin and the Chipmunks created by Ross Bagdasarian Sr. and the Chipettes created by Janice Karman. It is the second installment in the live-action Alvin and the Chipmunks film series and the sequel to Alvin and the Chipmunks (2007). The film stars Zachary Levi, David Cross and Jason Lee. Justin Long, Matthew Gray Gubler and Jesse McCartney return to voice the Chipmunks from the previous film. Christina Applegate, Anna Faris and Amy Poehler voice the new characters, the Chipettes. The film sees the Chipmunks entering high school and being under the care of Dave Seville's cousin, Toby, while Ian Hawke recruits the Chipettes to restore his career.

The Chipettes are a fictional girl group from the Alvin and the Chipmunks franchise consisting of three female anthropomorphic chipmunk singers: Brittany, Jeanette and Eleanor, alongside their adoptive human mother, Beatrice Miller. They first appeared in the animated television series Alvin and the Chipmunks in 1983. In this and related materials, Brittany and the Chipettes served as female featured characters in their own right, starring in numerous episodes. The title of the show was changed from Alvin and the Chipmunks to simply The Chipmunks in 1988 to reflect this. In the animated television series and the 1987 animated film The Chipmunk Adventure, all of the Chipettes were voiced by their creator, Janice Karman, the wife of Ross Bagdasarian Jr.. Karman also wrote and voiced the Chipettes' dialogue on their studio albums, while studio singers Susan Boyd, Shelby Daniel and Katherine Coon provided their singing voices. In the animated television series Alvinnn!!! and the Chipmunks, Eleanor is voiced by Vanessa Bagdasarian, the daughter of Ross Bagdasarian Jr. and Janice Karman.