Banstead-born comedian David Walliams is to join Olympic rower James Cracknell on a charity swim, row and cycle from Britain to Africa.

Cracknell sets off next month on the cross-continent challenge to raise money for Sports Relief.

The challenge involves rowing across the English Channel, cycling almost 1,400 miles through France and Spain then swimming the Strait of Gibraltar.

Walliams is to join him on the last leg, the 12-mile swim from Europe to Africa.

The 36-year-old Little Britain star last year swam the English Channel to raise money for the charity.