Where’s this joke from?

I’ve been watching the latest season of Comedians in Cars getting Coffee. In one episode Ricky Gervais tell a joke, but he can’t remember the source:

A holocaust survivor dies and goes to heaven.
When he arrives, he tells God a holocaust joke.
God says “That’s not funny”
The survivor replies “I guess you had to be there”

Seinfeld’s reaction was “That’s not a joke, it’s a novel!”

Any idea where it came from?

This article attributes it to David Baddiel.

Wow, that was fast. Thanks.