After being replaced as prime minister in 2019 by Boris Johnson, Mrs May began delivering paid speeches. That year alone she made nearly £400,000 from private engagements.
In June 2020 it was reported Mrs May had earned one million pounds from eight speaking events, averaging over £100,000 per address.
Writing in The Spectator Mr Morgan said he told Mr Trump the former prime minister “gets paid more than £100,000 a pop for speeches”.
In response the former president “exploded into mocking laughter”.
Mr Trump added: “Are you kidding me? I’d pay £100,000 not to hear her talk!”
Mrs May had a tense relationship with her US counterpart whilst at 10 Downing Street.
The two leaders clashed over NATO, the Iran nuclear deal and Mr Trump sharing videos from far-right group Britain First.
Last year CNN published an article by Carl Bernstein, one of the two journalists who uncovered the Watergate Scandal, claiming Mr Trump regularly “bullied and humiliated” the British Prime Minister.
He wrote: “He’d get agitated about something with Theresa May, then he’d get nasty with her on the phone call.”
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Mrs May became Prime Minister in July 2016 shortly after Britain voted to leave the European Union.
However Parliament repeatedly voted down her Brexit deal and she was forced to step down.
Mr Morgan has a longstanding relationship with Mr Trump, conducting a number of interviews during his presidency.
In 2009 the former Good Morning Britain host won The Celebrity Apprentice, a show hosted by the future president.
But In 2020 Mr Morgan was fiercely critical of Mr Trump’s handling of the coronavirus pandemic.
He claimed the US president unfollowed him on Twitter “when I told him to shut the bleep up about coronavirus”.
However in November Mr Morgan said he still considers Mr Trump to be “a friend”.
In March Mr Morgan left Good Morning Britain following controversial remarks about the Duchess of Sussex.
He said he “did not believe” claims she made in an interview with US talk show legend Oprah Winfrey.
This sparked 41,000 complaints to regulator Ofcom.