Jason Lee

Dave

David Cross

Ian

Cameron Richardson

Claire

Jane Lynch

Gail

Justin Long

Alvin (voice)

Matthew Gray Gubler

Simon (voice)

Jesse McCartney

Theodore (voice)

Veronica Alicino

Amy

Allison Karman

Female Intern #1

Tiara Parker

Female Intern #2

Kira Verrastro

Female Intern #3

Beth Riesgraf

Mother in Store

Adriane Lenox

Vet

Don Tiffany

Engineer

Frank Maharajh

Barry

Kevin Symons

Ted

Jayden Lund

Security Guard

Alexis Boyd

Dancer (as Alexis A. Boyd)

Kyndra Reevey

Dancer (as Kyndra 'Binkie' Reevey)

Natalie Cohen

Poolside Girl

Kevin Fung

Boy at the Grocery Store

Jillian Warry Barberie

Herself

Greg 'G-Spot' Siebel

Photographer

Oliver Muirhead

Butler

Erin Chambers

Press Coordinator

Adam Riancho

French Doll (voice)

Axel Alba

Spanish Doll (voice)

Rosero McCoy

Choreographer

Criscilla Anderson

Dancer

Tucker Barkley

Dancer

Celestina Aladekoba

Dancer

Laura Edwards

Dancer

Christopher Scott

Dancer

Miss Prissy

Dancer

Bryan Gaw

Dancer

Michelle Maniscalco

Dancer

Nick Drago

Dancer

Melanie Lewis

Dancer

Ross Bagdasarian, Jr.

Alvin (singing voice) (uncredited)

Janice Karman

Theodore (singing voice) (uncredited)

Steve Vining

Simon (singing voice) (uncredited)

Sommer Fehmel

Fan (uncredited)

Lisa Mason Lee

Band Member (uncredited)

Rae Sunshine Lee

Concert Attendee (uncredited)

Eddie Mariano

Concert Fan (uncredited)

Meghan Noone

Alvin's Fan (uncredited)

Chris Rossi

Dancer (uncredited)

Jameel Saleem

Band Roadie (uncredited)

Brianna Womick

Girl Hit by Stuffed Chipmunk (uncredited)

Gregg Lee

Concert Attendee (uncredited)