Jason Lee as Dave

Justin Long as Alvin (voice)

Matthew Gray Gubler as Simon (voice)

Jesse McCartney as Theodore (voice)

Kimberly Williams-Paisley as Samantha

Josh Green as Miles

Tony Hale as Agent Suggs

Bella Thorne as Ashley Grey

Eddie Steeples as Barry

Christina Applegate as Brittany (voice)

Kaley Cuoco as Eleanor (voice)

Anna Faris as Jeanette (voice)

Jose D. Xuconoxtli Jr. as Party Cop #1

Keith Arthur Bolden as Party Cop #2

Joshua Mikel as Wyatt the Pizza Guy

Jeremy Ray Taylor as Kid

Mike Senior as Paparazzi #1

Zeeko Zaki as Paparazzi #2

Jennifer Coolidge as Ms. Price

Uzo Aduba as TSA Officer

Jesica Ahlberg as First Class Flight Attendant

Derryl Rivers as Cab Coordinator

Retta as Party Planner

John Lacy as Owner

B.J. Winfrey as Clapping Person

Mark Jeffrey Miller as Cab Driver

John Kap as Giant Bearded Guy

Kevin Wayne as Large Cowboy

Tracy Goode as Bus Driver

Denitra Isler as Ticket Agent

Flula Borg as Man Behind Mask

Candace B. Harris as Airline Ticket Agent

Justin Miles as Young Employee

Laura Marano as Hotel Babysitter

David DeSantos as Maitre'd

Shatoya McClintock as Alice

Joseph Lavender as American Idol Bad Auditioner

Hakim Callender as Passing Record Executive

Benny Demus as DJ

Gabrielle Lexa as Fan #1

Brooke A. Belcher as Fan #2

Onira Tarés as First Record Executive

Leticia Jimenez as Second Record Executive

Charmin Lee as Judge

Ellie Knaus as Anna

Stefan Gordy as DJ at Party

Elyse Dufour as Access Hollywood Reporter

Kit Hoover as Access Hollywood Anchor

Autumn Monroe as Parade Woman

John Waters as First Class Passenger

Daryn Kahn as Party Guy

Parker Wierling as Miniature Golf Boy

Greg Pitts as Pool Attendant

Jennifer Joelle Blau as Waitress Passing Lady

Lisandra Silva as Female Bartender

Jelani A. Jackson as Brass Band Member

Nigel J. Burnett as Brass Band Member

Edward Williams as Brass Band Member

Saunders Sermons as Brass Band Member

Ryan Kilgore as Brass Band Member

Clarence Levy III as Brass Band Member

Stephen D. Wilson as Brass Band Member

Edward Platenburg as Brass Band Member

Jonathan Rosenblit as "Alvin" Reader

Ryan Girard as "Simon" Reader

Ronald Ogden as "Theodore" Reader

Katrine Hoyt as Shelbourne Hotel Guest (voice) (uncredited)

Ross Bagdasarian, Jr. as Alvin (singing voice) (uncredited)

Ken La Kier as Photographer (uncredited)

Janice Karman as Theodore / The Chipettes (singing voice) (uncredited)