She won double skulls gold with partner Anna Watkins at Eton Dorney in 2012, to add to silver medals from Sydney 2000, Athens 2004 and Beijing 2008.

However, the 38-year-old is swapping the water for the road as she takes on the marathon challenge on April 13.

"I am delighted to announce that, on behalf of International Inspiration, I will be able to fulfil a long standing ambition and run the 2014 London Marathon," said the six-time world champion.

"Starting my training, I've realised that this challenge will fully push me out of my comfort zone as an Olympic rower.

"But International Inspiration is about making a difference to people's lives and providing opportunities where there weren't any before and I'm proud to play my part.

"I want to raise awareness of the charity's fantastic work, which has already helped to inspire and transform the lives of over 15 million children, young and disadvantaged people around the world through the power of sport."

International Inspiration was formed exactly a year ago through the merger of the II Foundation (IIF) and International Development through Sport (IDS) to form International Inspiration:  'International Development through Sport' (IN).

The charity says it aims to increase opportunities for children and young people in low and middle income countries to access, enjoy and learn from physical education, sport and play.

Its programmes help develop young people to play their role in society, developing their leadership potential through sport and widening access to sustainable livelihoods.

The charity is chaired by British Olympic Association chairman Sebastian Coe.

Coe promised in 2005 to "reach young people all around the world and connect them to the inspirational power of sport" after he led London's successful bid for the 2012 Olympic and Paralympic Games.