Last week, the President blasted Mrs May's Brexit plan as not what the British people voted for in an interview with The Sun. "In fact, I told Theresa May what I thought she should do and she disagreed", he said.
Yesterday Mrs May pointed to Mr Trump's inconsistent advice when she said that as well as telling her to "sue" the European Union, he also suggested not walking away from the negotiations.
When asked on Sunday if she would stand if a Conservative Party leadership contest was triggered, May declined to directly answer saying: "I am in this for the long term".
Speaking to Morgan in an interview which will air on Good Morning Britain on Monday, he said: 'When I say lovely, inside and out, that is a attractive woman'.
He went on to say: "Let me tell you what I can talk about; she is an incredible woman, she is so sharp, she is so lovely, when I say attractive - inside and out".
So usually that helps.
'Just very elegant. And very lovely.
'She is so sharp, so wise, so attractive.
Trump also took a jab at Democrats, adding that no Democrat could beat him: "I don't see anybody". We met, but also watching the guard, hearing the sounds, being in that place, that very special place.
The comments shocked many in Britain - even May's opponents - and couldn't have come at a worse time for the British prime minister, who is facing a crisis over Brexit from within her own ranks.
In addition to criticizing May's handling of Brexit negotiations, Trump has gone after many of his European NATO allies for relying on the US for trade and defence spending, and called the EU a trade "foe" in an interview with CBS on Saturday.
One thing all sides agree and what the PM made very clear is that the clock is ticking. Somebody said are you friends or enemies?
"I didn't criticize the prime minister", Trump said. She said it's a very - and she's right - it's a very complex problem, I think nobody had any idea how complex that was going to be.
President Donald Trump hinted that the world's largest economy could strike "a tremendously big deal" with United Kingdom, if the latter country successfully negotiates its exit from the European Union.
Morgan's interview with Mr Trump airs on ITV's Good Morning Britain at 6am BST on Monday.
Saying the EU is "very hard", Trump berated the 28-member union over trade - complaining that European nations have taken advantage of the United States. "We're going to get it".
In his interview with Morgan, Trump said the United States and its longtime ally would "argue, we're going to fight, and we're going to end up making a deal". But the charges shine an even brighter spotlight on Trump's treatment of Putin, who has repeatedly denied that Russian Federation sought to skew the election that Trump, a Republican, unexpectedly won.