David Gilmour and Roger WatersThose wishing for a Pink Floyd reunion perpetually need to be reminded not to hold their breath, however fans were right to anticipate an onstage collaboration between ex-bandmates Roger Waters and David Gilmour this year.

The pair previously announced that Gilmour would sit-in with Waters for one song at an unspecified date during Waters' current, worldwide 'The Wall Live' tour, which was based largely on Pink Floyd's 1980 'The Wall' tour. Most people assumed that the collaboration probably wasn't going to happen during the U.S. leg of the tour last year.

The moment that everyone had been waiting for came -- and passed all too quickly -- on Thursday (May 12) at the O2 Arena in London.