Michael Sheen and David Tennant teasing and dancing aroung THE spoiler in Good Omens Season 1 :) (watch)
Interviewer: Was there ever any interest in you playing Crowley and David playing Aziraphale?
Michael: We sort of... we tell the story, don't we, that when they do the theatrical tour of this, we'll just swap parts every night.
David: We alternate.
Interviewer: I love that. That would be so much fun. And then people would have to come twice.
Michael: Exactly.
David: Yes. You see, it's a gold mine.
Michael: And without giving any spoilers away...
David: Oh, be careful, go gently.
Michael: ...there may be, if you watch the show, at somepoint, an opportunity to see how that might work.
Interviewer: Okay, I think I know what you might mean.
David: Okay. All right. Say no more.