Brown arrived in the United States
Gordon Brown has arrived in the United States for his first meeting with new president Barack Obama, BBC reported.
The UK prime minister said the effects of the two countries' economic bailout packages would be "magnified" if they worked closely together.
Mr Brown also told TalkSport radio he was "impressed" by Mr Obama, with whom he will hold talks on Tuesday.
The prime minister is the first European leader to meet Mr Obama since he became president in January.
Mr Brown will also address a joint session of Congress on Wednesday.
Speaking on TalkSport, the prime minister said: "I think first of all to meet him [Mr Obama] as a person, you cannot but be impressed by his demeanour, his determination, not just his fluency, but his sympathy for the causes he represents.
"I think the impression he has given of America to the world is transformative, because he is a black man who has won the presidency, who is living in the White House that was built by slaves."
He added: "I think people's view of America is changing as a result of that."
Mr Obama was facing "very difficult" economic decisions after taking office in the middle of a crisis and "doing similar things to what we are doing in Britain", Mr Brown said.
Following an EU summit at the weekend, the prime minister said he would take a "clear message" from European leaders that "bold global action" was needed to tackle the economic crisis.
The EU and Canada have warned that a "Buy American" clause in the US economic recovery package could promote protectionism.
It seeks to ensure that only US iron, steel and manufactured goods are used in construction work funded by the bill - but has included a pledge to respect international trade obligations.
Mr Brown's meeting with Mr Obama comes ahead of the G20 summit of the world's biggest economies in London next month - in which Mr Brown has said it is vital that world leaders "take the big decisions necessary to secure our economic future".