Guitarist Phil Collen tells us that the vocal we hear on Def Leppard’s “Armageddon It” was just laid down as a guide for the musicians — and that they didn’t expect it would end up on final mix of the song.

“We’ve done guide vocals before. I do them. Sometimes they’re not even words. You go ‘[sings gibberish].’ That’s it, and it stays until something a little more solid. Then there’s a few more words come in, then there’s a sentence. You go, ‘Oh, OK, this makes sense and it suggests something else.’ But with that one, we thought it was pretty much a guide right until the end until we went, ‘You know what? Don’t touch it. It’s great.”

Def Leppard bassist Rick Savage celebrates his 60th birthday today!