A woman detained over suspicions she may be involved in the apparent assassination of North Korean leader Kim Jong-un’s brother may have been a contestant on Vietnam’s version of Pop Idol, it has been claimed.

Doan Thi Huong, who is currently being detained by Malaysian police, bears a striking resemblance to a woman who appeared on the show in June 2016.

The 28-year-old Vietnamese singer also reportedly posted a picture of herself to social media days before Kim Jong-nam was killed wearing a t-shirt with “LOL” on the front, similar to the one shown in CCTV images of the suspects fleeing, the Mirror reports.

However North Korean diplomats have called for the immediate release of “innocent females” arrested in connection with the 46-year-old's death.

Ms Doan and an Indonesian woman were detained last week after CCTV footage appeared to show them approaching Mr Kim at Kuala Lumpar International airport on 13 February, before allegedly putting a substance on his face.

Some local media outlets have claimed that the pair were duped into allegedly playing a role in the killing after being told it was a television prank.

But Malaysian police chief Khalid Abu Bakar disputed this. He said the suspects were “trained” and had even practised the attack at different public places, including a major mall in downtown Kuala Lumpur.

“Yes, the two female suspects knew that the substance they had was toxic," he said. "We don’t know what kind of chemical was used. They used their bare hands.”

He added that they were instructed to wash their hands afterwards.

North Korea’s ambassador to Malaysia has meanwhile insisted that the man who died in the airport is not Kim Jong-un's brother and that Malaysia’s investigation into the death cannot be trusted.

Mr Kim, who was estranged from his younger brother and lived with his wife and two children in Macau on the south coast of China, had previously spoken out against his family’s dynastic control of North Korea.