"It's a blessing, an absolute blessing," Halford tells Billboard. "It's remarkable, isn't it? What's really heartwarming about this is the fact that the so-called old guard of metal and rock are still as strong and thriving as we ever were.

"I have very close friends like [Black] Sabbath, who released a fantastic metal album [2013's 13] and went out on this huge world tour. They've been together longer than we have. Then you get [Iron] Maiden, then bands like Metallica, doing that type of process."

"All the bands that have been making this music for a very long time are still as strong and relevant as they ever were, so we're part of some very good company."