Nova Dolittle
Jenna Coleman

Robert Downey Jr.
John Dolittle

Kasia Smutniak
Lily Dolittle

Harry Collett
Tommy Stubbins

Antonio Banderas
King Rassouli

Micheal Sheen
Blair Müdfly

Jim Broadbent
Lord Thomas Badgley

Carmel Laniado
Lady Rose

As well as:

Emma Thompson - Poly (voice)
Rami Malek - Chee-Chee (voice)
John Cena - Yoshi (voice)
Kumail Nanjiani - Plimpton (voice)
Octavia Spencer - Dab-Dab (voice)
Tom Holland - Jip (voice)
Craig Robinson - Kevin (voice)