Gordon Brown and President Barack Obama said they will aim to reach an agreement at the G20 Summit to help the people hit hardest by the economic crisis.
In a joint press conference in London, the two men said they wanted to focus on the "human dimension" of the crisis and ensure that help is provided for people around the world who are losing their jobs, homes and savings.
They rejected concerns that the Summit, which will take place in East London tomorrow, may not reach an agreement or lead to any concrete action.
The Prime Minister said: "The world does want to come together. Britain and America working together can help reach consensus - not just something that is reached on paper but something that can help people everywhere."
The President said: "All of us here in London have a responsibility to act with a sense of urgency and I think what Gordon spoke about - the human dimension of this crisis… that’s what our agenda has to begin with and that’s where it will end."
Mr Brown and President Obama also emphasised the importance of the "special relationship" between the UK and the US, and their own personal friendship.
Earlier in the morning, the two leaders had met at Downing Street to discuss the G20. Their ambitions to create a low-carbon economic recovery, and UK and US involvement in Afghanistan were also on the agenda.
President Obama and his wife Michelle had joined Gordon and Sarah Brown for breakfast at Downing Street, and will later meet the Queen at Buckingham Palace.