Theresa May has revealed that Donald Trump advised her to sue the EU rather than negotiate Brexit.
Following their meeting at Chequers on Friday, the US president said he had given the prime minister a "suggestion" but that she "found it maybe too brutal".
Asked on BBC1's The Andrew Marr Show what his advice had been, she said: "He told me I should sue the EU. Not go into negotiation, sue them."
She added: "What the president also said at that press conference was 'Don't walk away. Don't walk away from the negotiations. Then you're stuck'."
At their press conference on Friday, Mr Trump said of the suggestion: "I can fully understand why she thought it was a little bit tough."
Mrs May also insisted that her controversial blueprint for Brexit represents a "good deal" for the UK.
Amid mounting Tory anger over her proposal for a "common rule book" with the EU on trade in goods, she acknowledged she had been forced to make changes to her original plans by Brussels.
However she said that result was a plan that would deliver "benefits" for Britain, protecting jobs and ensuring there would be no need for a hard border between Northern Ireland and the Republic.
Mrs May defended her revised Brexit plan, agreed by the Cabinet at Chequers, which led to the resignations of David Davis and Boris Johnson.
"This is a good deal for the UK. In this one area we needed to make a change - the question of trade in goods in relationship to the frictionless border - we needed to make a change," she said.
"We needed to come forward with another option to in order to ensure that we can get those negotiations on trade. The clock is ticking.
"But this a deal that has benefits. Our companies will abide by these rules anyway, Giving them frictionless border means that the jobs that depend on that frictionless trade will be protected.
"It means we deliver on the Northern Ireland border. It means we have got benefits out of this deal. This is a good deal for the UK."