Finance ministers from the world's richest countries have gathered in London in an attempt to approve a debt relief deal to help Africa's poor.
High-profile celebrities are backing the poverty campaigners at the G8
The talks come just a month before world leaders - and thousands of anti-poverty campaigners - converge at Gleneagles in Scotland for a G8 summit.
Britain has vowed to make poverty reduction a key plank of the summit.
Its plans got a boost as the White House confirmed the US and UK had agreed on how to implement debt cuts.
The BBC's Steve Schifferes at the meeting says Germany, France and Japan had been doubtful about a total debt write-off - so having US support may help the UK win them over.
After a breakfast meeting with the finance ministers, South Africa's finance minister Trevor Manuel said that he was optimistic that a deal was on the cards.
"The fact that the US is in there now is exceedingly important for us," he said. " I have a very strong sense that the agreement will be struck."
UK Chancellor Gordon Brown on Friday expressed optimism that a debt deal would be done, saying that there was the "political will of the richest countries to move forward".
He also promised that it would be "the biggest debt settlement the world has ever seen".
The finance ministers are spending Saturday morning discussing the outline plan from the UK and US to write off the debts of 18 highly-indebted countries in Africa, White House spokesman Scott McClellan said.
He added that the plan would "cancel 100% of the World Bank, African Development Bank and IMF debt" - suggesting the US may have dropped objections to including IMF debts.
African officials generally welcomed the prospect of a deal.
John Nagenda, an adviser to Ugandan President Yoweri Museveni, told the BBC it was time for rich nations to deliver on their promises.
"I should be more apologetic and say please help us but where I come from we believe that if you are better off than someone else you help them. It's as simple as that - it's a moral duty."
Ghanaian Environment and Science Minister Christine Churcher said that if the debt was cancelled, her country would spend the extra money on education, health and improving the water supply.
Funding the plan remains controversial. The US has previously said any debt relief from the World Bank should come out of funds the organisation uses to lend to poor countries.
Mr McClellan said debt would only be cancelled for countries that showed a commitment to "sound economic policies" and reducing corruption.
Germany, France and Japan have proposed that the rich countries shoulder the costs of servicing poor nations debt, rather than write off the debts entirely.
However, Canada, which had earlier backed these plans, now appears to be moving to support a complete write-off.
The finance ministers are hoping to make progress on deep-seated disagreements over key proposals to boost aid to Africa, as well as cutting debt.
Our correspondent says that despite a plea from UK Prime Minister Tony Blair, the US is unlikely to support a doubling in aid flows to poor countries.
Nor does the US favour a French proposal to tax international airline travel to fund additional aid.
The development lobby, which is organising mass demonstrations during the summit, wants finance ministers to agree debt relief for all poor countries, double aid to $100bn a year, and reform the world trading system.
The G8 countries are United States, Canada, Britain, France, Germany, Italy, Japan and Russia.
The 27 countries who are eligible for debt relief under the HIPC (highly-indebted poor countries initiative) and the 18 who have reached completion point in bold: Benin, Bolivia, Burkina Faso, Cameroon, Chad, Democratic Republic of Congo, Ethiopia, Gambia, Ghana, Guinea, Guinea Bissau, Guyana, Honduras, Madagascar, Malawi, Mali, Mauritania, Mozambique, Nicaragua, Niger, Rwanda, Sao Tome Principe, Senegal, Sierra Leone, Tanzania, Uganda, and Zambia.
The 11 countries who theoretically qualify for debt relief but have not been allowed to join so far are: Angola, Burundi, Central African Republic, Ivory Coast, Comoros, Congo, Liberia, Burma, Somalia, Sudan, Togo.
Jubilee Debt Campaign argue that the figures show that another 24 countries qualify as needing full debt relief if they are to have the resources necessary to meet the Millennium Development Goals: Azerbaijan, Bangladesh, Cambodia, Equatorial Guinea, Eritrea, Georgia, Haiti, India, Indonesia, Kenya, Korea, Kyrgyz Republic, Lesotho, Nepal, Moldova, Nigeria, Pakistan, Sri Lanka, Tajikistan, Uzbekistan, Vanuatu, Vietnam, Yemen and Zimbabwe.