Quote from George in The Pitch/The Ticket
Jerry: And who is on the show? Who are the characters? George: I could be a character. Jerry: You? George: Yeah. You could base a character on me. Jerry: So, on the show, there's a character named George Costanza? George: Yeah. What, there's something wrong with that? I'm a character. People are always saying to me, "You know, you're a quite a character." Jerry: And who else is on the show? George: Elaine could be a character. Kramer... Jerry: Now, he's a character.