Jazz Carlin: Welsh double Olympic medallist to launch 'crazy' medal bid
Double Olympic silver medallist Jazz Carlin will bid to become the first woman to win medals in both the pool and open water at the same Olympics.
The 27-year-old, who was second in the 400m and 800m freestyle at Rio 2016, is taking up 10km marathon swimming and considering racing in the new women's 1500m event at Tokyo 2020.
She could challenge for a record haul of four medals - a feat which has never been achieved by a British swimmer.
"People think I'm crazy," said Carlin.
"I'm terrified of jellyfish as well, but it's all new and a really fresh test."
The Welsh swimmer will race in her first 10km event at the FINA World Cup in China next week.
But Carlin, who missed London 2012 after suffering glandular fever - says she suffered a severe case of "Olympic blues" following Rio 2016 and felt as though she "lacked purpose" in life.
Her struggles resulted in her withdrawing from this summer's World Championships in Budapest, but taking up open-water swimming has "revitalised" her love for the sport.
"I was nervous, but I haven't felt like that for years," she told BBC Sport.