To save you a click:

The Southern Television broadcast interruption was a broadcast signal intrusion that occurred on 26 November 1977 in parts of southern England in the United Kingdom. The audio of a Southern Television broadcast was replaced by a voice claiming to represent the ‘Ashtar Galactic Command’, delivering a message instructing humanity to abandon its weapons so it could participate in a ‘future awakening’ and ‘achieve a higher state of evolution’. After six minutes, the broadcast returned to its scheduled programme.