The PM has told that she aims to charm Donald Trump into backing a trade deal, declaring that "sometimes opposites attract".
Theresa May also believes she is able to endear US President Donald Trump into backing NATO, the UN and even the EU.
Speaking to reporters on her flight to the US, Mrs May said President Trump shared some of her political values, and that of Brexit Britain.
She said: "I think we both share a desire to ensure that governments work for everyone and particularly that governments are working for ordinary working class families.
"I think that's important. That's what I've spoken about. I did it on steps of Downing Street when I became Prime Minister; a country that works for everyone and an economy that works for everyone.
"I think we share that interest and that intention in both our countries."
Asked ahead of her White House meeting tomorrow about the contrast between a vicar's daughter and a reality TV star, Mrs May joked: "Have you ever noticed that sometimes opposites attract?"
The PM said she was pleased to be going to the White House "so early" in the administration - just a week after President Trump's inauguration.
Mrs May declined to criticise the President's crackdown on immigration.
She said: "The rules that the US introduces are rules for the US."
And also would not be drawn on his controversial claims about millions of illegal voters.
"What happens in US elections is not a matter for the British PM. It is a matter for US and US authorities," she said.
The PM also signalled a significant toughening on the language around Iran's nuclear deal, signed in 2015.
"On the question of the Iran nuclear deal, I think it was an important deal that was done and I think it is important that we ensure that the deal is properly enforced," she added.
President Trump has suggested scrapping the deal.
Some Conservative MPs have warned against getting too close to the controversial property tycoon.
Conservative chair the of the Commons Health Committee Sarah Woolaston today went public with her criticism.
The PM said: "Donald Trump was elected president of the USA. The UK and US have shared interests and shared challenges we can work together to deal with.
"We have a special relationship. It's a longstanding relationship. It's existed through many different PMs and Presidents.
"I believe there is a shared role for UK and US Working together; we can stand up for shared interests and shared values."
The PM is meeting with Congressional Republican leaders in Philadelphia on her first stop, and will become the first foreign leader at the Trump White House tomorrow.