Originally, Aunt Jackie was supposed to watch The Chipmunks after Dave broke his leg, but she fell down an escalator at the airport and had to go to the hospital, leaving them in Toby's care.
Jackie is a kind, elderly lady in a wheelchair. She lives with her grandson Toby, who she claims is "living with her until he figures out what he wants to do with his life, and so far that involves going 'pew pew pew' with his thumbs all day." She is rather strict with Toby.
Alvin calls her "Popcorn Jackie," since she gives popcorn on Christmas.
Some fans believed she could be the replacement for Miss Miller.
In the film's end credits, in a photo, Aunt Jackie is shown to have healed from her injury and is celebrating Christmas with the Seville family.