Legendary LED ZEPPELIN guitarist JIMMY PAGE made a surprise appearance onstage at a DONOVAN show in London last Friday.  Well, it was supposed to be a surprise for the crowd... Donovan knew what was up.

Jimmy played his solo from the 1965 hit "Sunshine Superman"... and he also joined in during "Mellow Yellow".

Donovan said, quote, "In 1965, Jimmy had just left the Yardbirds and hadn't started on Zeppelin yet.  So we hired him to do a session at Abbey Road... though he's known for his power guitar, Jimmy is a real folk aficionado."

And Jimmy agreed... quote, "A lot of my songs were written on the acoustic guitar.  And so much of the first album of Led Zeppelin was acoustic, too."

The London Contemporary Orchestra was also backing up Donovan at the concert.

(Here's video of the "Sunshine Superman" collaboration.)

(Here's a clip of Donovan and Jimmy playing "Mellow Yellow".  Jimmy is standing with his back to the camera at the right side of the screen.)