Yes, they did, it's called Good Omens. But it has been so long that I read it, that I hardly remember what it was about. I just remember that I liked it, because that was what made me read other Geilman books.
I've read every single Book by Terry Prattchet expect maybe 4 or 5?

I have his last book, The Shepherd's Crown, still here, waiting to be read, so that would be one I could suggest. But I think it's Tiffany Aching-book, so it's rather for a younger audience? I have to look up which ones of his other books I am still missing. We have probably over 60 Terry Prettchet books here, so it's hard to keep track.