Fu recalls that the staff of the Chinese embassy in Cambodia were confined to the embassy, which was monitored by a local military force sent by Nol after China refused to recognize his regime.

She, who was 29 at the time, was recruited to work for a Chinese government office that looked after Sihanouk and his family after the coup.

He recalls that Zhou gave Sihanouk a warm welcome when he arrived in Beijing after being overthrown in the coup.

But Sihanouk's friendship with Zhou can be traced back to the 1955 Bandung Conference, a large-scale international meeting to unite Asian and African countries.

After private meetings with Zhou at the Bandung Conference, Sihanouk visited China twice, paving the way for the two countries to establish diplomatic relations in 1958.

Among the many stories told in the documentary is one about Sihanouk and his wife Monineath paying their first state visit to China in February in 1956.

When they arrived they didn't have winter clothes. So, Zhou asked some local tailors to quickly make outfits for them, which Sihanouk cherished and wore every winter while he was in China.

While the first four episodes look back at Sihanouk and his close connections with China, the fifth episode focuses on the more recent past.

And it talks of 1992, when China sent peacekeeping personnel to Cambodia following the call of Boutros Boutros-Ghali, the then secretary-general of the United Nations.

Li, the director of the TV documentary, says Ma Jidong, a team leader of a military engineering unit of the Chinese peacekeeping force, told him the temperature there was more than 40 C. It was a very harsh environment for Chinese soldiers, who contributed a lot to the friendship between China and Cambodia.