The television personality, who is launching the annual charity event alongside comedian Carr, said that she recently took part in a long-distance cycle ride to prepare for the event.
Cotton said: "I'm a huge fan of Sport Relief and thoroughly enjoyed whipping Jimmy Carr into shape for this year's campaign - especially having spent five days of the last Sport Relief in a team cycling non-stop from John O'Groats to Lands End, and Jimmy just popped along for one day. Sweet revenge!"
Sports Relief takes place between March 23 and March 25.
The Sainsbury's Sport Relief Mile, which raises money for vulnerable people in the UK and some of the world's poorest countries, takes place on Sunday, March 25 and will feature some celebrity runners including Xtra Factor host Olly Murs, actress Kara Tointon and Lorraine Kelly.
Comic Relief chief executive Kevin Cahill revealed on BBC One's Breakfast that he hopes 1 million people will take part in this year's Sport Relief Mile.
Boyband JLS have written and recorded the official Sport Relief single entitled 'Proud'. They will also perform a one-off concert to mark the event at The O2 on Saturday, March 24.
Comedian and Britain's Got Talent judge David Walliams has previously raised money for the Sport Relief cause, swinning 140 miles along the River Thames to raise over £1 million for the charity.
Eddie Izzard also ran 43 marathons in 51 days for the cause in 2009.
Blue Peter presenter Helen Skelton is currently undertaking a 500-mile trek across Antarctica to the South Pole over the Christmas and New Year period.
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