In The Spirit Of The Day...

From Wiki:

Vrillon, representative of the Ashtar Galactic Command was the name used by an unidentified voice who broadcast on the transmitters of Southern Television in the United Kingdom for about five minutes at 5:10 PM on Saturday November 26, 1977. The voice, which was disguised and accompanied by a deep buzzing, broke in to a broadcast by Independent Television News to warn viewers of "the destiny of your race" and "so that you may communicate to your fellow beings the course you must take to avoid a disaster which threatens your world and the beings on other worlds around you".

I am actually old enough remember the news reports re this broadcast. It was a big deal for a day or two. But don't think I've ever heard the whole thing from end to end before. The hoax perpetrator was never caught and never heard from again.