Michael Cera

Gunther

Jack O'Connell

Mr. Hartman

Charles Grodin

Father

Kelis

Herself

Brandon Reilly

Dougie

Curtiss Cook

Conrad

Charlotte Booker

Mrs. Hartman

Andy Prosky

Dr. Schwartz

Christina Sajous

Backup Singer

Deonna Bouyue

Backup Singer

Himanshu Suri

Recording Engineer

Andrew Levine

Adler

Adam Levite

Man in Recording Studio

Caroline Capers Powers

Dr. Schwartz's Date

Michael Cera