"I mean they have a lot of great product".
Mrs May will host Mr Trump and his wife Melania at a lavish dinner at Blenheim Palace this evening.
The Wycombe MP revealed that DExEU, set up in the wake of the Leave vote in June 2016, had been working on a white paper entirely different to the one the Prime Minister had sprung on ministers at Chequers, and that Brexiteers appeared to have been victims of "a year's worth of cloak and dagger to land us into the Chequers position", with the Cabinet-level department having served as a kind of "Potemkin structure" to give the impression that the Prime Minister was working on a real Brexit, while her European Union unit at the Cabinet Office was undermining them behind the scenes.
"He told me I should sue the EU". It's not what they want, and on top of that when they hear that Leave voters are unhappy, they ask, "What's the point?"
The amendments to be voted on Monday are unlikely to pass without Labour support, but they represent a show of power by Brexiteer MPs toward the prime minister.
Trump undermined May's proposal when he said the blueprint would "probably kill" prospects for a UK-US trade deal in an interview with The Sun published on Friday.
Mrs May said it was "all of our responsibility to ensure that transatlantic unity endures".
"I think maybe she found it too brutal", he said, standing alongside Mrs May, without revealing the details.
"We will do a trade deal with them and with others around the rest of the world", she added.
The threat from the Brexiteers is not the only danger facing Mrs May, with pro-EU Tories tabling amendments of their own to the Customs Bill and the Trade Bill - which returns to the Commons on Tuesday - which would keep Britain in a customs union with the EU.
He was speaking ahead of a meeting in Brussels on Monday with the EU's chief negotiator Michel Barnier.
"She's a very smart, very tough, very capable person and I would much rather have her as my friend than my enemy, that I can tell you", he added.
But he repeated his praise of Mr Johnson, saying: "Boris Johnson, I think, would be a great prime minister".
'It is time for all of us - at this critical moment in our constitutional development - to believe in ourselves, to believe in the British people and what they can do, and in our democracy, ' he wrote.
"It has to reflect on the issues of the three red lines [leaving the single market; leaving the customs union; and ending the jurisdiction of the European Court of Justice] which I believe most Conservative MPs want to see reinstated and it has got to come up with a position which accommodates that".