I'm aching to go and see it, been a while since I last visited a movie theatre.
But if anyone can convince me, it would be Morgan Freeman alongside Tom Cruise on a post-apocalyptic Earth.
I've been asking myself that question too.
According to wiki: (brace for copypasta)
So I guess it wasn't in the comic books, but it hasn't been grasped out of nowhere either.
On a side note: EPIC TRAILER. DO WANT TO WATCH.