At first glance, the former chief of an aluminium firm and the rock star appear to have little in common, reports the BBC, previewing next week's Africa trip.

U2 star Bono will team up with US Treasury Secretary Paul O'Neill for a 10-day tour of the poorest countries in sub-Saharan Africa.

O'Neill, the former chief of the world's largest aluminium firm seems to have little in common with the eccentric Irish rock star.

But Bono's campaigning against third world debt has made headway in Washington DC, with the U2 frontman gaining the ear of the president.

Now Bono will join O'Neill for whistlestop visits to Ghana, Uganda, South Africa and Ethiopia.

The plan was formed after a meeting in O'Neill's office a year ago, a discussion the treasury secretary says he was initially very reluctant to have.

"I said, 'He just wants to use me and I don't have time for this'," O'Neill explained recently.

He relented and agreed to a 30-minute meeting which expanded into a 90-minute brainstorming session with O'Neill coming away impressed at the depth of Bono's knowledge and commitment.

"He understood economic theory and he understood the impact of colonialism.

"He knew what it was like to go into an HIV-AIDS clinic and see three people in a bed all dying together and care about it and know it doesn't have to be that way," O'Neill said.

Bono's interest in Africa goes back at least to U2's participation in Live Aid. He and his wife spent six weeks working in an orphanage in Ethiopia to learn how bad conditions were.

Since then, he has become a tireless campaigner for debt to be written off and positive action taken to improve life in Africa.

Heavily involved in the Jubilee campaign, he is also a founder of Debt, Aid, Trade for Africa (DATA).

Since the 11 September attacks, leaders in the west have acknowledged that tackling poverty and maintaining global security are linked.

Bono met President George W Bush in March for the announcement of an increase in the development budget to $40bn (£27.5bn).

At the time he said: "I am a pest. I am a stone in the shoe of a lot of people living here in this town, a squeaky wheel."

But the extra US money comes with conditions with the money being given only to countries that are working to fight corruption and reform their economies.

O'Neill backs this stance, arguing trillions of dollars in aid has been wasted. The Africa trip starts on Monday 20 May with O'Neill and Bono visiting schools, AIDS clinics and various World Bank development projects.

"It is possible for the two of us to see life through each other's eyes," O'Neill said last week in previewing the trip.

More at news.bbc.co.uk