AC/DC's Brian Johnson joined The Foo Fighters on stage at "VAX Live: The Concert to Reunite the World" over the weekend.
The concert was organised by the charity Global Citizen to celebrate the worldwide availability of COVID-19 vaccines, with the audience largely made up of vaccinated healthcare and essential workers.
Before the audience were aware that AC/DC's frontman was about to come onto stage, Grohl announced:
"Considering that this is the first show that we've done in, I dunno, a year and a half, a long time - we thought that we would make this a special occasion... So say you wanna do something special, what do you do?
"You call a friend to come play with you, right?"
Johnson and the Foo's then performed AC/DC's 1980 hit 'Back in Black.'
Check it out up top.