Team GB sponsors commissioned the 12ft (3.6m) by 40ft (12m) floating fibreglass sculpture to help spur British athletes to victory.
Ms Adlington, who won the 400m and 800m Freestlye in the Beijing Games in 2008 and bronze in the same events at London 2012, is depicted swimming freestyle across the lake in London's Hyde Park.
But, it is not the first time a giant inflatable has taken to the water in London.
There was the time a giant rubber duck came floating down the Thames in 2011 to promote an online bingo site.
And the time a giant wooden hippo was towed from the Royal Docks to the 02 Arena. It was created by Dutch artist Florentijn Hofman for the month-long Totally Thames culture show in 2014.
And who could forget the Michael Jackson statue floated down the Thames as part of the HIStory Tour promotion in 1995?
In the build up to London 2012 the Olympic rings were sent down the Thames to mark 150 days until the Opening Ceremony.
Team GB sponsors hope Ms Adlington's statue will also lift spirits and encourage the public to get behind the British athletes once more.
Rio 2016 starts on 5 August.
A giant sculpture of two-time Olympic gold medallist Rebecca Adlington has popped up in the Serpentine lake ahead of the Games in Rio.