Grohl said in Portland, Oregon, this week: "I have a note from my doctor - although I'm really into the idea of a conspiracy theory. What if I didn't break my f***ing leg? What if I jumped off stage, fell on the ground and made it all look like it was a f***ing emergency?

"They dragged me off to the side, the band keeps playing, then 10 minutes later I magically reappear. Then I get somebody else's X-ray of a broken leg, make it into a T-shirt and we make millions of f***ing dollars.