David Gilmour and Jeff Beck Play "Jerusalem" and "Hi Ho Silver Lining" in 2009

Here's something you don't see every day.

On July 4, 2009, attendees of Jeff Beck's sold-out show at London's Royal Albert Hall got a bit of a bonus during the encore: an on-stage visit by Pink Floyd legend David Gilmour.

Gilmour—whose brief appearance was a complete surprise to everyone in the audience—picked up his black Strat, and the band launched into an extended guitar-heavy instrumental version of "Jerusalem," a Sir Hubert Parry-penned hymn from 1916 that was inspired by an influential William Blake poem of the same name.

Up next (and last) was "Hi Ho Silver Lining," Beck's 1967 debut solo single. The song is always a crowd pleaser, especially in the U.K., where it actually charted. Beck sings on the track (a true rarity), and Gilmour pitched in on vocals—and lead guitar—for this occasion. You can watch clips of both songs above.

If the site of these two Strat masters sharing a stage looks vaguely familiar, it might be because they performed together at the Royal Albert Hall on April 1, 2004, when they both participated in the Teenage Cancer Trust concert.