The BBC is to screen Ewan McGregor's latest motorcycle odyssey, Long Way Down.

Actor McGregor and friend Charley Boorman will travel 15,000 miles from John O'Groats to the southernmost tip of South Africa.

Their trip will be turned into a six-part documentary series for BBC2.

Long Way Down is the follow-up to Long Way Round, which saw them circumnavigate the globe and was screened on Sky One.

McGregor, 36, said: "Long Way Round changed us all - it bonded us together and made our dreams come true - and it's not often something like that happens. So to be given another opportunity to do something like this is amazing."

The series raised over £100,000 for Unicef and Long Way Down will also raise money for charity.

It will last three months and take in 20 countries.

Most of the journey will be spent in Africa and McGregor hopes to highlight the continent's mounting problems of Aids, hunger and malaria.

McGregor and Boorman set off this weekend and the series will be broadcast in the autumn.

Their progress can be followed via blogs and video clips of their travels will be posted on YouTube.

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