How mint would this have been to see live.
Brian Johnson joined Muse on stage at the Reading Festival in England to perform AC/DC's most iconic track, Back in Black.
Muse frontman Matt Bellamy belted out "He's back!" before they launched into the classic tune.
It's Johnson's second time on stage since he had to leave AC/DC in March 2016 due to hearing issues.
"Thank you so much. Thank you, boys" Johnson said after the performance.
Check out some videos of it below.