There are not many countries in the world that Diana, Princess of Wales didn't have a profound effect upon.

Ahead of the 20th anniversary of the late royal's death on 31 August, it has emerged that North Korea once issued a tribute to the 'People's Princess'. Despite the East Asian country being separated from the rest of the world, Prince Charles and Diana's wedding in 1981 at St Pauls Cathedral in London led to celebrations in the hermit kingdom.

Surprisingly, the birth of Prince William in 1982 prompted further support from the secretive state. In a random tribute to the royals, they were immortalised in a series of commemorative stamps that were sold in the country's capital of Pyongyang during the rule of Kim Il-sung.

One collection of stamps were marked "DPR Korea" and featured Charles and Diana at their wedding. Another set released in 1982 marked Diana's 21<sup>st birthday.

But the bizarre stamp tributes weren't just in aid of adoration for the British royals – they were released in an attempt to raise money for the hard-up regime.

The head of Asia studies at the University of British Columbia in Canada, Ross King, believes they were sold as collectors' items, telling CNN: "In the broad scheme of things, collector-oriented stamps far outweigh those with a political message.

"They even had Princess Diana on the stamps back in the 80s when they thought that Brits were buying stamps. The US is another country that uses the postal service to make a ton of money off gullible collectors."

"Most of them don't have a high market value. New issues, in mint condition, sell for around $0.50 (39p).

"But they're just printing paper – which is worth nothing – and receiving valuable dollars for it. It's more or less free money.

"Nobody in Europe or North America collects stamps anymore. Now, they're pushing Chinese themes because they know collectors are buying them," he added.

Similarly to Western countries' postal services, North Korea also designs stamps to commemorate national achievements and world events – with typical subjects including the Ryugyong Hotel and the 2014 World Cup, though they failed to qualify for it.