Theresa May has evoked the memory of Margaret Thatcher and Ronald Reagan as she called on the USA to renew its special relationship with the UK.
Speaking to congressmen from the Republican Party of President Donald Trump in Philadelphia, Mrs May said the two countries had a "responsibility" to come together and offer leadership to the rest of the world.
She signalled support for some of Mr Trump's key foreign policy priorities, condemning the "malign influence" of Iran, vowing to fight so-called Islamic State - also known as Daesh - and promising to "stand up" for the security of Israel.
And she echoed Mr Trump's criticism of the US/UK invasion of Iraq under Tony Blair and George Bush, saying that there must be "no return to the failed policies of the past - the days of Britain and America intervening in sovereign countries in an attempt to remake the world in our own image are over".
Mrs May's pointed references to the close Reagan-Thatcher relationship will fuel suspicions that she is hoping for a similar partnership with Mr Trump, who has reportedly started referring to the Prime Minister as "my Maggie".
Asked by reporters whether she would struggle, as a reserved vicar's daughter, to strike a rapport with the brash property tycoon and reality TV star, Mrs May said: "Haven't you heard? Sometimes opposites attract."
But the PM also sounded notes of caution over foreign policy positions taken by Mr Trump on the campaign trail, warning that his watchword with Vladimir Putin's Russia should be "engage but beware".
She described the Iran nuclear deal - which Mr Trump has threatened to tear up - as "vitally important for regional security". And she spoke out in support of the importance of international institutions like the UN, IMF and Nato, often the target of Mr Trump's scorn, in maintaining global peace and prosperity.
Speaking a day ahead of the White House meeting that will make her the first foreign leader to meet Mr Trump since last week's inauguration, Mrs May made no attempt to dissuade her audience from drawing parallels with the US and UK leaders of the Cold War era.
Countries in central and eastern Europe were free "because of the leadership of Britain and America, and of Mrs Thatcher and President Reagan", she said.
She warned: "We should not jeopardise the freedoms that President Reagan and Mrs Thatcher brought to Eastern Europe by accepting President Putin's claim that it is now in his sphere of influence."
In a clear attempt to mend fences with a man whose campaign policies she once described as "divisive, stupid and wrong", Mrs May went out of her way to praise Mr Trump's election victory and stress common threads between the Conservatives and Republicans, winning five standing ovations from her audience.
Both parties believe in "the value of liberty, the dignity of work, the principles of nationhood, family, economic prudence, patriotism - and putting power in the hands of the people," she said.
And she said Mr Trump's victory would allow the US to be "stronger, greater, and more confident in the years ahead", just as the Brexit vote would restore Britain's sovereignty and independence.
Speaking shortly after voicing differences with Mr Trump on the use of torture, Mrs May said: "There may be occasions on which we disagree. But the common values and interests that bring us together are hugely powerful."
She dismissed those who predict "the eclipse of the West" in the face of emerging giants like China and India and the threats of economic instability and Islamist terrorism.
The US and UK had a "joint responsibility to lead, because when others step up as we step back, it is bad for America, for Britain and the world," said Mrs May.
"The world is passing through a period of change - and in response to that change we can either be passive bystanders, or we can take the opportunity once more to lead. And to lead together.
"I believe it is in our national interest to do so. Because the world is increasingly marked by instability and threats that threaten to undermine our way of life and the very things that we hold dear."
Mrs May is the first foreign head of government to address the annual Republican Congressmen's Retreat.
In a sign of her determination to deepen links with the Republican establishment as well as the team around Mr Trump, she held private talks with House of Representatives Speaker Paul Ryan and Senate majority leader Mitch McConnell, as well as the Foreign Affairs Committee chairmen of the two houses of Congress, Ed Royce and Bob Corker.