Pink Floyd was a British progressive rock group, active from the end of the 1960s until the early 1980s. They are best known for their best selling albums "Dark Side Of The Moon" (1973) and "The Wall" (1979).
According to various sources Zappa and Pink Floyd performed "Interstellar Overdrive" together during the Actuel Festival in Amougies, Belgium. Zappa himself denied this, however, when he was interviewed about the matter in They're Doing the Interview of the Century, Part 2. Photographs and audio recordings suggest otherwise. 
On April 2, 1980, Zappa played Pink Floyd's "Another Brick In The Wall, Part 2", when he was a guest deejay on radio station KSJO, San Jose.
"Frank Zappa is really one of those rare musicians that can play with us. The little he did in Amougies was terribly correct. But he’s the exception. Our music and the way we behave on stage, makes it very hard to improvise with us." - Pink Floyd member Nick Mason, 1973.