Almost exactly a year and half since what may have been his last show with AC/DC, Brian Johnson made a surprise return to one of the world's largest stages by performing "Back in Black" alongside Muse at the Reading Festival.

The hugely popular alternative rock band, which was closing out this year's edition of one of the world's most famous festivals, invited Johnson out to perform the title track of his first album as AC/DC's singer with a simple "he's back!"

As you can see in the above video, the crowd went absolutely bonkers, singing along with the song's famous guitar riff and cheering every one of Johnson's moves and utterances. As the song came to its conclusion, a clearly thrilled Johnson declared, "That means a lot to me, thank you so much, thank you boys!" and gave a big, and possibly rib-crushing, bear hug to Muse singer Matt Bellamy.

This is Johnson's second surprise live appearance since doctors forced him to depart AC/DC's chaotic Rock or Bust tour (check out the details below) in February 2016 out of fear that he could face total hearing loss. In May 2017, he sang the Motown classic "Money (That's What I Want)" alongside Robert Plant and Paul Rodgers in Oxford, England.

AC/DC eventually completed the tour with Guns N' Roses frontman Axl Rose filling in on vocals, but have given no indication of their plans for future tours or new albums. Johnson, meanwhile, has been meeting with the inventors of a new type of in-ear monitor that could potentially allow him to return to his craft full time.

Revisiting AC/DC's Chaotic 'Rock or Bust' Tour