Gerald Hamer (1886–1972) was a Welsh actor, best known for his character roles in Hollywood films of the 1930s and 1940s. Specializing in the portrayal of sinister, ambiguous, or neurotic characters, he was often cast as a red herring in mystery plots. His fame is particularly linked to his participation in several films of the Sherlock Holmes series starring Basil Rathbone, where he excelled at creating an atmosphere of suspicion. Among his most memorable performances are his roles in *The Pearl of Death* (1944), as the unsettling postman Potts, and in *Terror by Night* (1946). Although he never achieved leading man status, Hamer is remembered by genre enthusiasts for his ability to bring to life supporting characters of great impact and psychological tension, contributing significantly to the success of classic mystery films. His career, though not extensive, is recognized for the incisiveness of his performances in specific roles that made him an iconic face of mystery cinema of the era.