Some 26 leaders, including Russian President Vladimir Putin and Iranian President Masoud Pezeshkian, will also attend the parade that will showcase China's latest equipment and see Xi Jinping inspect troops in Beijing's Tiananmen Square.

Millions of Chinese people were killed during a prolonged war with imperial Japan in the 1930s and 40s, which became part of a global conflict following Tokyo's attack on Pearl Harbor in 1941.

Beijing's Communist Party has held a series of blockbuster events in recent years to commemorate its wartime resistance, vowing that China will never be brought to its knees in such a way again.

The parade on September 3 will feature ground troops marching in formation, armoured columns, aerial echelons and other high-tech fighting gear.

China has touted the parade as a show of unity with other countries.

Beijing's assistant minister of foreign affairs, Hong Lei, announced Kim's attendance at a press conference on Thursday morning.

"The Chinese people will join hands with the people of all countries to firmly defend the victories of World War II," Hong told reporters.

"At present, the international situation is marked by intertwined turbulence and changes, with the deficit in world peace continuing to grow," he added.

Pyongyang's official Korean Central News Agency also announced the visit, saying Kim will be a guest "at the invitation of Comrade Xi Jinping".

- 'Cannot be bullied' -

China is North Korea's most important ally, their relationship forged in the bloodshed of the Korean War in the 1950s.

Beijing has historically provided diplomatic, economic and political support to the country, which remains under crippling international sanctions.

Kim's upcoming visit to Beijing is intended to show "the strength" of the ties between the two countries, said Chong Ja Ian, an associate professor of political science at the National University of Singapore.

The visit would signal that "the United States cannot bully them into submission", Chong told AFP.

There was "some talk previously that (North Korea) has gone closer to Moscow's orbit at the expense of Beijing", said Dylan Loh, an assistant professor at Singapore's Nanyang Technological University.

"That may still unfold but I think Kim's visit underlines the fact that this relationship is still going strong," Loh told AFP.

"It will also further demonstrate the influence and pulling power of China," he added.

- 'Traditional friendship' -

Assistant foreign minister Hong said that developing "the traditional friendship" between the two countries was Beijing's "firm position".

"China is willing to continue to strengthen exchanges and cooperation with North Korea...work closely in promoting regional peace and stability and safeguarding international fairness and justice," he added.

The North Korean leader last visited China in January 2019 for talks with Xi and had skipped Beijing's 2015 parade.

China's third highest-ranking official Zhao Leji visited North Korea in April last year, as the two countries marked 75 years of diplomatic ties.

Chinese people used to make up the bulk of foreign tourists and business visitors to the isolated nuclear nation before it sealed its borders during the Covid-19 pandemic.

North Korea has built a secret military base near its border with China, which may house Pyongyang's newest long-range ballistic missiles, research published this month showed.