A look-alike is a person who closely resembles another person. In popular Western culture, a look-alike is a person who bears a close physical resemblance to a celebrity, politician or member of royalty. Many look-alikes earn a living by making guest appearances at public events or performing on television or film, playing the person they resemble. A large variety of celebrity-lookalike images can be found throughout the web, including images placed by professional agencies that offer their services.

Source: Wikipedia.org