As American policemen in London, Bud and Lou meet up with Dr. Jekyll and Mr. Hyde.
Bud Abbott
as Slim
Lou Costello
as Tubby
Boris Karloff
as Dr. Henry Jekyll / Mr. Hyde
Craig Stevens
as Bruce Adams
Helen Westcott
as Vicky Edwards
Reginald Denny
as Inspector
John Dierkes
as Batley
Eddie Parker
as Mr. Hyde (uncredited)
Patti McKaye
as Can-can dancer
Betty Tyler
as Can-can dancer
Lucille Lamarr
as Can-can dancer
Dante De Paolo
as Specialty dancer