Russell Brand
Arthur

Helen Mirren
Hobson

Greta Gerwig
Naomi Quinn

Jennifer Garner
Susan Johnson

Geraldine James
Vivienne

Luis Guzmán
Bitterman

Nick Nolte
Burt Johnson

Peter Van Wagner
Naomi's Dad

Christina Jacquelyn Calph
Tiffany

John Hodgman
Peter, Candy Store Manager

Murphy Guyer
Officer Kaplan

Saul Stein
Officer #2

José Ramón Rosario
Employment Clerk

John Hodgman
Candy Store Manager

Scott Adsit
Gummy Bear Man

Evander Holyfield
Boxing Trainer

Robert Clohessy
Veteran Cop

Ed Herbstman
Rookie Cop

Jared Parker
Wedding Kid

Richard Bekins
Chancellor

Matt Malloy
Spoon Guy

Nigel Barker
Photographer

Tuffy Questell
Tito

Sara Chase
Journalist #1

Ali Reza
Journalist #2

Charlie Hewson
Receptionist / Best Man

Peter Brouwer
Auctioneer

Stink Fisher
Foreman

Pascal Yen-Pfister
Maitre D'

Dylan Clark Marshall
Boy on Tour

Steve Rosen
Grand Central Waiter

Leslie Hendrix
Alice Johnson

John Carrafa
Choreographer

Sean Tarjyoto
Bookstore Clerk

Pamela Stewart
Librarian

Skai Jackson
Library Girl #1

Tori Feinstein
Library Girl #2

Jackson Nicoll
Library Boy #1

Devin Almonte
Susan's Bridesmaid (uncredited)

Jamie Choi
Bridesmaid (uncredited)

Tatsumi Romano
Tour Girl (uncredited)

Chelsey Donn
Clerk (uncredited)