Chet is a very tall surgeon at Sacred Heart.
Chet is extremely tall, his face is never seen (he's too tall to be contained in a single frame). When J.D. needs to borrow a spare set of scrubs, he asks Chet. They are extremely long on him though. ("My Overkill") That makes them very useful in order to create the Giant Doctor persona with Turk, Lonnie or Elliot. ("My Clean Break")