The Ugly Duckling (1959)

Henry Jeckle (Bernard Bresslaw) was always the outsider, a bungling and awkward buffoon, relegated to waiting for his invitation to participate in life that never arrived: until he discovers a medical formula developed by a dead uncle, which claimed to turn 'a man of timid disposition into a bold, fearless dragon'. Taking a draught of the elixir Henry is transformed into suave, sophisticated and highly desirable Teddy Hyde (also Bernard Bresslaw). Armed with his new persona, Teddy is ready to face the world; but is Henry ready for the consequences?