The reunion was months in the making. Last summer, Waters and Gilmour, who had a falling out during the making of 1983's The Final Cut, buried the hatchet to perform at a benefit concert for the Hoping Foundation. (It was the first time they played together since 2005's Live 8 show in London, which was their first show in 24 years.) Gilmour promised to join Waters for one of his Wall shows if he participated in the charity show.
"How could I refuse such an offer?" Waters wrote on his Facebook page. Ten months later, Gilmour made good on his end of the bargain, which was made even sweeter with the addition of drummer Mason for a rendition of "Outside the Wall." (Pink Floyd keyboardist Rick Wright died in 2008.)
Despite Gilmour and Waters reunion, Gilmour says it was definitely a one-off. A post on his official site reads, "David is not repeating his special guest performance for a later occasion."