WATCH: AC/DC Unearth Throwback 1981 "You Shook Me All Night Long" Live Video
The band is celebrating 40 years of "Back in Black" all month long.
Even the world's biggest rock stars get nostalgic sometimes. Such was the case when AC/DC singer Brian Johnson hosted Metallica drummer Lars Ulrich on his rock and roll TV show, Brian Johnson's A Life on the Road.
It was back in 1991 when AC/DC brought Metallica out on the Monsters of Rock tour, and a mutual admiration between the two bands was formed.