Vrillon Ashtar Galactic Command Radio Incident 1977
The Southern Television broadcast interruption was a broadcast signal intrusion that occurred on 26 November 1977 in parts of Southern England. The audio of a Southern Television broadcast was replaced by a voice claiming to represent the 'Ashtar Galactic Command'. The speaker delivered 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.
https://www.youtube.com/watch?v=q9zZumLdwk8