According to Marilyn Monroe, a popular American actress and model, "diamonds are a girl's best friend." She famously sang this line in the 1953 movie "Gentlemen Prefer Blondes." The quote has since become a popular phrase when referring to the love and admiration many people have for diamonds. It represents the concept that diamonds, which are precious stones associated with luxury and wealth, are a symbol of everlasting love and beauty and can make any girl feel special.