Humphrey Bogart
The captain of the The African Queen, Charlie Allnut, was written as a Cockney from England. Bogart was not able to reproduce that distinctive yet idiosyncratic accent, so Charlie’s biography was rewritten to make him Canadian. Despite the fact that most viewers would have a hard time identifying the character as Canadian, his performance earned him—amazingly—his first Oscar nomination since Casablanca nearly a decade earlier. Bogart would be nominated a third time for The Caine Mutiny just three years later but by then he would be an Academy Award winner for Best Actor in this film.
Katherine Hepburn
By contrast, The African Queen would bring co-star Katherine Hepburn her fifth Oscar nomination, though she would lose out when Vivien Leigh collected her second Best Actress statue for A Streetcar Named Desire. Disgusted by the copious amounts of liquor being consumed by both Bogart and director John Huston—no doubt inspired by her attempts to deal with longtime lover Spencer Tracy’s alcoholism—Hepburn chose to forego spirits and drink only water. This turned out to be unwise as she suffered from dysentery throughout much of the shoot.
Robert Morley
Almost most of the film was actually shot on location in Africa, Robert Morley never left the comfort of England for his part as the missionary brother of Hepburn’s character. All his scenes were shot in a studio in London and then carefully edited to make it appear as though he had been on the set in African with the rest of the cast.
Theodore Bikel
The African Queen was the first substantial film appearance by acclaimed character actor Theodore Bikel. He started out playing a foreigner and seemed always to be on call whenever casting agents were looking for someone exotic and slightly sinister. He would enjoy a career that spanned more than half a century, seeming to show up in a guest role on nearly every well-known TV series of the 60's and 70's. He may be most familiar to modern viewers as the man in the Twilight Zone episode who warns that come 4:00 PM all the "nasty" people in the world he has spent his adult life trying to make miserable because he disagrees with their values will under a sudden transformation. A transformation does come, but with the standard Twilight Zone twist.
