Coldplay brought Michael J. Fox on stage to perform with them during their headlining Glastonbury set on Saturday.
Fox, who memorably played Chuck Berry's Johnny B. Goode on guitar in Back to the Future, and has been battling Parkinson's Disease since 1991, was introduced by frontman Chris Martin ahead of their song Fix You.
"With his Chuck Berry riff and the way he punched Biff: ladies and gentlemen, please welcome Michael J. Fox," Martin said as the actor took the stage in a wheelchair and played guitar during Fix You and Humankind.
Afterwards, Martin added: "The main reason we're in a band is because of Back to the Future. So thank you to Michael, our hero."
The rocker also honoured Glastonbury founder Michael Eavis with a touching on-stage tribute.
Martin serenaded the 88-year-old farmer turned festival impresario, who was sat at the side of the stage, by singing: "As humans go you're the best of all sorts. You're a musical charmer, you're the world's greatest farmer. Whoever got knighted wearing shorts?"
Martin added, "Thank you Michael, thank you for everything, we love you, everybody loves you," and asked the huge Pyramid stage crowd to cheer the Glastonbury chief to show their appreciation.
Eavis founded the event that would go on to be known as Glastonbury as the Pilton Pop Folk & Blues Festival in 1970, and his daughter Emily is now its main organiser.
Coldplay's set meant they are the first band to headline five times - having previously done so in 2002, 2005, 2011, and 2016.
In addition to a slew of their biggest hits, Coldplay also performed a new track, a collaboration with U.K. rapper Little Simz, which is rumoured to be called Supernova.