The Prime Minister dismissed predictions of a character clash between the brash New York property tycoon and reality TV star and the reserved daughter of an English vicar when they meet face-to-face for the first time on Friday.
Mrs May promised she will speak up for British interests in White House talks expected to focus on trade, security and the future of the UK-US special relationship - insisting that what she says to the President will not differ from what she says in public.
And she played down the likelihood that policy differences over issues like Nato, Iran and the use of torture might stand in the way of the closer relationship which she believes is in the interests of both Britain and America.
Speaking to reporters on her flight to the US, Mrs May said: “We have an opportunity through this early meeting with Donald Trump to start that process of building on that special relationship - a special relationship which is in our national interest and I think is in their national interest.
“And I think that we can together not just build that special relationship, but do it in a way that is good for both of us and good more widely.”
Although no talks on a formal free trade agreement can begin until the UK leaves the EU, Mrs May made clear she hopes to use the Oval Office meeting to start tearing down barriers to trade.
There was much that could be done now to “remove some of the barriers to trade in a number of areas, so we are able to see an advantage to both of us even if we haven’t been able to sign that legal free trade agreement”, she said.
Mrs May said the President had already assured her in a phone conversation of his “commitment” to Nato.
And she insisted that Mr Trump’s apparent readiness to use torture and “black site” prison camps against terror suspects would not alter the UK’s stance, telling reporters: “We condemn torture and my view on that won’t change whether I’m talking to you or talking to the President of the United States of America.”
In a speech to Republican congressmen on Thursday, Mrs May was due to say that Mr Trump’s election and the Brexit referendum have provided the two countries with an opportunity to “renew” their links, restore their confidence and “lead together again” in the world.
Asked whether she saw parallels between their approaches, she said: “I think we both share a desire to make sure that governments are working for everyone and that particularly governments are working for ordinary working families and working-class families.
“I think that’s important. That’s what I spoke about on the steps of Number 10 when I became Prime Minister. I think we share that interest and that intention in both our countries.”
Mrs May laughed off suggestions that their contrasting personalities might prove a barrier to a good working relationship with Mr Trump, asking reporters: “Haven’t you ever noticed that sometimes opposites attract?”
And she dismissed the suggestion that she may not be able to trust a politician who has shown himself willing to repeat in public assertions which have been comprehensively written off as false.
Asked whether she feared that UK voters may think she is getting too close, too quickly with a president about whom many have deep misgivings, Mrs May said: “Donald Trump was elected President of the United States of America.
“The United Kingdom and the USA have shared interests, shared challenges that we can work together to deal with.
“We have a special relationship. It is a long-standing relationship, it’s existed through many different prime ministers and presidents.
“I want to build on that relationship. I believe from the conversations I’ve already had with Donald Trump he does too.
“I believe there’s a role for the UK and the US working together that we can play in standing up for our shared interests and our shared values.”
She added: “What is important is actually being able to have the opportunity to sit down with President Trump and talk to him face-to-face about the issues, about the interests we share, about the special relationship, about the challenges that we both face.”