Wikipedia
The GRUNK, a French acronym for Royal Government of the National Union of Kampuchea , was a government-in-exile of Cambodia, based in Beijing, that was in existence between 1970 and 1976. Officially, it was briefly in control of Cambodia between 1975 and 1976.
The GRUNK was based on a coalition (the FUNK, acronym for "National United Front of Kampuchea" ) between the supporters of exiled Head of State Prince Norodom Sihanouk and the Khmer Rouge ("Red Khmer", an appellation he had himself coined for the members of the Communist Party of Kampuchea). It was formed, with Chinese backing, shortly after Sihanouk had been deposed in the Cambodian coup of 1970; the Khmer Rouge insurgents had until that point been fighting Sihanouk's Sangkum regime.