The 27-year-old, winner of Olympic silver medals in both the women’s 400 and 800 metres freestyle events at Rio 2016, is due to compete at the penultimate leg of this year’s World Cup series in Chun'an County in China.

It marks the start of her bid to claim glory in both swimming disciplines at a single Olympics, with Tokyo 2020 now less than three years away.

Only Tunisia's Oussama Mellouli has previously managed to achieve the feat having won men’s 10 kilometres marathon gold and 1,500m freestyle bronze at London 2012.

"People think I'm crazy and ask if you get punched [in the open water]," Carlin, who took a year out after Rio 2016, was reported as saying by BBC Sport.

"I'm terrified of jellyfish as well, but it's all new and a really fresh test.

"The danger with training for the longer distances is you can lose the speed you need for the shorter ones."

The Welshwoman added: "I think I have a really great opportunity to be a part of open water and still try and get on that pool team, and it's quite exciting to think that you could make history in an event.

"I'm very happy with two silvers, but you know it's Tokyo and why not go for gold, hey?

"I'm a bit greedy I guess."

Carlin insisted she is still very focused on the women’s 400m and 800m events as well, as the 1,500m, recently added to the Olympic programme for Tokyo 2020.

Her more immediate aim, however, is to make an impact on Chun'an County's Qiandao Lake before competing again over 10km in the final leg of the World Cup series in Hong Kong on October 21.

Chun'an County is hosting the sixth leg of this year’s World Cup.

The first three stops were Patagones-Viedma in Argentina, United Arab Emirates’ capital Abu Dhabi and Portuguese city Setúbal.

The two most recent legs were held in Canada with Lac Saint-Jean and Lac-Mégantic playing host.