As American policemen in London, Bud and Lou meet up with Dr. Jekyll and Mr. Hyde.
| Actor | Role |
|---|---|
 Bud AbbottSlim | Slim |
 Lou CostelloTubby | Tubby |
 Boris KarloffDr. Henry Jekyll / Mr. Hyde | Dr. Henry Jekyll / Mr. Hyde |
 Craig StevensBruce Adams | Bruce Adams |
 Helen WestcottVicky Edwards | Vicky Edwards |
 Reginald DennyInspector | Inspector |
 John DierkesBatley | Batley |
 Eddie ParkerMr. Hyde (uncredited) | Mr. Hyde (uncredited) |
| PPatti McKayeCan-can dancer | Can-can dancer |
| BBetty TylerCan-can dancer | Can-can dancer |
| LLucille LamarrCan-can dancer | Can-can dancer |
| DDante De PaoloSpecialty dancer | Specialty dancer |
 Carmen De LavalladeJavanese dancer | Javanese dancer |
| MMaisay KawasumaJavanese dancer | Javanese dancer |
| HHenry CodenJavanese actor | Javanese actor |
 Marjorie BennettMilitant woman | Militant woman |
| IIsabelle DwanMrs. Penprase | Mrs. Penprase |
| JJames FairfaxMr. Penprase | Mr. Penprase |
 Harry WilsonMan Asking for Match | Man Asking for Match |
 Harry CordingRough Character in the Park | Rough Character in the Park |