I always say no to adapting my own stuff. People get grumpy with me, because they think I should be adapting my stuff. And I go, "Well… I already wrote it once. I already wrote the book."

But with this, it was like: Okay. Terry is gone. He wanted me to do this. He wanted me to do it for him. And that gave me a kind of weird impetus. And it meant that I felt very much at liberty to take every conversation that Terry and I had ever had about Good Omens. Not just the book, as written, but everything beyond it. We planned a sequel, never written, so I got to steal the angels from the sequel. I got to steal from every conversation Terry and I had about how we would do this. It felt very personal, and I guess kind of… holy. If that doesn’t sound too ridiculous. But it was a mission.

Over the years, you’ve seen many people people tackle adaptations of your work. For Good Omens, why did you decide to be show runner?

I’ve had too many experiences in television where you write a script and you hand it over to people. And maybe you get back something that wins awards, and maybe you get something where people go, "Ugh, that was a piece of rubbish." But the truth is, the two scripts might have been relatively similar in quality in content. The difference is how the story gets approached, and how it gets sold, and who directs it, and so forth.

This time, I was determined that if I was going to do it, I was going to do the whole thing. So I was in casting, and I put myself on the line to Amazon for the director [Douglas Mackinnon]. It was like, "I want Douglas. I know you guys want some fancy movie directors, but I think Douglas has the skill necessary to bring this in. And I’m not sure an Oscar-winning movie director would actually, necessarily, be able to make this thing."

Let’s talk about the cast. How did you end up with Frances McDormand as the voice of God?

It was magic, serendipity, and luck. I knew that I wanted somebody American, smart, and powerful. And I knew it probably couldn’t be Whoopi Goldberg, because she had already played God, the Devil, and Death.

So I was trying to come up with somebody new, and toying around a bit with the idea of approaching Meryl Streep, because I knew that she was fond of my three-year-old son, who she had sort of babysat at a gig backstage. But I thought, "I’m not sure that she’s exactly right. I mean, she can do anything, but I’m not sure." And as I was trying to come up with the perfect voice, I got an email, out of the blue, from Frances McDormand. It said, "You don’t know me, but I was given your email by a mutual friend who said that you have a house in this part of Scotland, and Joel and I are going. And the place we normally stay, we can’t. Is there any possibility of renting your house?" And I got to say, "No, you can’t rent it, because we never rent it to anybody. But I’d be happy for you to stay there." And then, having said that, I went to our director and said, "What would you think about Frances McDormand?" And he said, "Oh, God. That’d be amazing."

I thought, before I ask her, that I should listen to some of her stuff. So I listened to her audiobooks, and I loved them and I loved her delivery. She was wonderful. So I sent her another email, saying "How would you like to be the Voice of God? You get the house on Skye either way." Frances said yes, and she was amazing. When I had rewritten some lines following the edit, she was shooting a movie, and she gave up her only day off to record in a bathroom where they used towels to cover every wall, using the sound guy on her movie to set things up. She gave up a day for us that she didn’t have, as a result of which we would all dub her Saint Frances.