A 50-year-old woman has caused a stir on social media in China, after she posted photos of herself posing in bikinis in extreme cold.

The photos, which show Ms Liu Yelin clad in nothing more than a bikini and a pair of ski goggles, were posted on her Weibo account on Monday (March 19).

They were taken at the frozen Lake Baikal in Russia, north of the Mongolian border.

The mother of a 23-year-old said she exercises for hours each day, sometimes in the cold to help slow the ageing process, reported Chinese media.

Her exercise regime reportedly includes yoga in the snow and swimming in icy water - which she says is her "favourite thing to do".

Ms Liu first made the headlines last May, when her son reportedly said it was difficult for him to find a partner because people usually mistake his mother for his girlfriend.

According to Sinanews, the retired librarian from Henan province has been working out for 30 years, a habit that her son says is the secret to her good looks.

The self-professed "hot mum" has more than 153,000 followers on Weibo, where she posts exercise tips and photos of herself.

"My mum has always been beautiful. When she was young, she was considered the prettiest girl at her school," her son Xie Yixuan was quoted as saying by the Daily Mail last year.

"I'd say as time goes by, she's even prettier now," added Mr Xie, who works as a personal assistant at a film production company.

In March 2016, Ms Liu swam across the Strait of Malacca from the shores of Penang, and completed the swim in four hours.

She told the Daily Mail: "I want to stay this beautiful when I'm 80 years old."

She added she hopes to encourage women to keep exercising for a "more beautiful and confident self".