Rage Against The Machine have cancelled their forthcoming UK and European tour - forcing the Reading and Leeds festivals to replace them with The 1975 just two weeks ahead of their headline slots.
The band - who only recently returned to the stage after 11 years away - said it was due to the health of frontman Zack de la Rocha.
While his exact injury is not known, the 52-year-old singer injured his leg on stage in Chicago last month and has used a chair at gigs since the incident.
In a statement, Rage Against The Machine wrote: "Per medical guidance, Zack de la Rocha has been advised that the August and September 2022 UK and European leg of the Rage Against The Machine tour cannot proceed. It is with great disappoint that we announce this cancellation".
The band said they would be finishing the last three days of their US tour at Madison Square Garden in New York.
After that they said: "Zack must return home for rest and rehabilitation. The flights, travel time and rigorous schedule in the UK and Europe are simply too much of a risk for a complete recovery.
"We are sorry to all of our fans who have waited years to see us, and hope to Rage again soon."
The message listed the cancelled gigs and said refunds to any headline shows would be offered to ticketholders.
Their shows in France, Belgium, Germany, Switzerland, Spain, Austria, Poland, Croatia and the Czech Republic were also called off.
The rock group, made up of Zack de la Rocha, Brad Wilk, Tim Commerford and Tom Morello, are best known for the 1993 anti-authority anthem Killing in the Name.
Shortly after the band announced the cancellation, Reading and Leeds shared an updated line-up, with the message: "We heard you. The 1975 will now be headlining #RandL2. Don't say we never treat you."
The 1975 also shared the updated line-up.
The pop group, made up of Matty Healy, George Daniel, Adam Hann and Ross MacDonald, have not played live in the UK since 2020.
Their fifth studio album is due to be released later this year.
The Reading and Leeds festivals take place from 26 to 28 August.