dead ringer

 someone or something that looks very similar to someone or something else:

He's a dead ringer for James from JamesAgain.

NOUN

dead ringer (noun)

1. informal

   a person or thing that looks exactly like another.

   "he is a dead ringer for his late papa
2. an athlete or horse fraudulently substituted for another in a competition or event                                             "it was discovered that the winning horse was a ringer"
3. a person who is highly proficient at a particular skill or sport and is brought in to supplement a team or group of people.                                                                                                                                                                  "league eligibility rules had grown flexible to accommodate new teams, and ringers began suiting up"
4. a person or device that rings something.