No, it’s not an episode of V, it was a 1970s real-life hijacking of Southern Television in England by the “alien” Vrillon, as reported by The Kernel:
26 November 1977 was a deeply cold night in England. The regional station Southern Television was just beginning its evening news bulletin and families across South-East England gathered together in their living rooms to watch the news. Children waited impatiently for Looney Tunes, which they knew would be shown directly after the news programme.
As Andrew Gardner read out news of the conflict in Rhodesia, a hissing, shuffling sound drowned out his voice. Suddenly, a booming voice addressed the startled viewers, as the screen still showed the oblivious newsreader reading through the day’s headlines.
This is the voice of Vrillon, a representative of the Ashtar Galactic Command, speaking to you.
It was now ten past five in the evening. With the news report still continuing on the screen, the deep, oscillating voice continued with his message.