Two Degrees of Separation (from me) by PotatoD

Question 2

A good friend of mine teaches at a Manhattan private school for (among others) children of the rich and famous, so I'm probably two degrees of separation from a bunch of people, but she doesn't like to say who they are. But I do know that among the parents with whom she rubs elbows is this Indiana-born former weatherman better known for other pursuits. Name the celebrity.

David Letterman