|Also Known As||Marty (by Tommy Pickles)|
|Friends||Tommy Pickles (possibly)|
|Voice Actor||Michael Bell|
|First Appearance||"Truth or Consequences" (2003)|
|Last Appearance||"Petition This!" (2008) (poster only)|
Martin Costomiris is a character who appears in "All Grown Up!". He is a famous film director who Tommy looks up to and aspires to be. He appears in the episode "Truth or Consequences" as a poster in Tommy's room and as the judge for the student film contest. Though Tommy does not win the film contest, he was able to take a picture with Martin. He also makes cameo appearances throughout the series.
Martin Costomiris is depicted to be an elderly man with a light purple jacket and beret hat. He also has a white-grayish beard.
- In the episode "Truth or Consequences", Tommy talks to his poster in order to find out what he needs to do to patch up his friendships. After the conversation, Tommy jokingly says he's a little creeped out that he talked to a poster, but says he'll worry about it later.
- In "The Old and the Restless", Martin is seen sitting down on a chair in the museum and he quickly gets up to leave.
- In "Memoirs of a Finster", Martin is seen in the audience watching the Finsters perform their Kabuki dance. He is also seen laughing at the errors made in the dance.
- In "Saving Cynthia", Martin is seen at the Doll Convention purchasing an item.
- In "Izzy or Isn't He?", Martin is seen walking passed the Java Lava.