Meghan Markle had reportedly said in 2016 that she would leave the country if Trump became President.

Ahead of upcoming visit to the UK, Ireland and France next week, US President Donald Trump told a British daily that Meghan Markle, the Duchess of Sussex, was "nasty" in response to her 2016 comment where she called Trump "misogynistic".

Trump, in his Oval Office interview with the Sun newspaper published on Friday, weighed in on everything from outgoing UK Prime Minister Theresa May's handling of Brexit to the contenders vying to replace her to Markle's dislike of his politics, CNN reported.

During the interview, Trump was confronted by the comments made by Markle ahead of the 2016 US presidential election where she said on "The Nightly Show with Larry Wilmore" that Trump was misogynistic and that his politics was divisive. The then actress added that she would move to Canada if he won the presidency.

Trump responded: "I didn't know that she was nasty. I hope she is OK..."

He seemed to bury the hatchet saying: "I am sure she will go excellently (as a royal). She will be very good."

Regarding Brexit, Trump criticized May's efforts, saying he thought that "the UK allowed the European Union to have all the cards".

May will formally step down as Conservative Party leader on June 7 after all her withdrawal agreements were disagreed by her Cabinet members, forcing her to resign from office.

"I had mentioned to Theresa that you have got to build up your ammunition... I am sure that you could have built up a big advantage for your side and negotiated from strength.

"And it is very hard to play well when one side has all the advantage... They had nothing to lose. They didn't give the European Union anything to lose."

However, he acknowledged, "at the same time, I respect Theresa and she would certainly know the facts a lot better than I know them".

May's resignation will trigger a party leadership contest, and once a new party leader is in place she will no longer be Prime Minister, a process that could take weeks, if not months, CNN reported.

Trump expressed his support for former Foreign Secretary Boris Johnson, calling him "a very good guy, a very talented person".

"I think Boris would do a very good job," the President told The Sun. "I think he would be excellent."

He also showed favour for British Foreign Secretary Jeremy Hunt. "Yup, I like him," Trump added.