Westerners will know the principal singers of this clip from a Japanese television variety program as the very tiny magical and telepathic twin beings called "Shobijin" in 1964's Mothra vs. Godzilla. And the original Mothra from 1961, of course. As well as Ghidora, The Three Headed Monster , or 大怪獣 地球最大の決戦, lit. "Three Giant Monsters: Earth's Greatest Battle" also from 1964.
The duo are Emi and Yumi Ito a.k.a. The Peanuts.