He said: "Would it be the way I negotiate?"
But May will welcome his prediction - reinforced by US Treasury Secretary Steven Mnuchin in Davos - that the US could swiftly strike a post-Brexit trade deal with London.
Morgan, a vocal Arsenal fan and Wenger critic, used part of a one-on-one interview with the leader of the free world to discuss football.
"David Davis has supported her at every step and they are both supported by a very able Civil Service team".
President Donald Trump defended his positions on climate change, gun control and even his tweeting and eating habits during a rare, wide-ranging interview with British television personality Piers Morgan.
The president said he did not know whether he'd been invited to the May 19 nuptials, but said the pair look like a "lovely couple". "I think they want to be safe at home", he said, reiterating that although he is not a feminist, he has "tremendous respect for women".
In a recapping his interview with the president, Morgan detailed the moment he asked Trump the feminist question. "He's a friend of mine - Emmanuel".
"I don't want to be involved with people (like that)", he said, adding: "I am the least racist person that anybody is going to meet". "We had dinner at the top of the Eiffel Tower".
The interview was conducted on the sidelines of World Economic Forum in Davos, Switzerland on Thursday.
Reacting to the recent rally organised to mark the one-year anniversary of Women's March in Washington protesting Trump's presidency and his policies, he said: "You are always going to have marches.The march, I guess, was a lot smaller than it was last year".
"I have tremendous respect for women", he followed up.
The guest list for Harry and Markle's May 19 wedding at Windsor Castle has not been made public.
A Number 10 source said: "An invitation has been extended and accepted and details will be set out in due course". It is not clear if a final list has been drawn up.
Morgan accused the president of causing "huge anxiety and anger in my country, because Britain First is basically a bunch of racists, fascists".
The hour-long interview will air on ITV later today.
Trump told Morgan that he actually thought he was going to win the election in the final 30 days of the 2016 campaign and rubbished claims that he was unhappy with the result. Because of legal technicalities America can't get out until November of 2020.
"We love your country".
"I am a stable genius", he said, doubling down on his previous claim on Twitter that a simple "smart" is an epithet too weak to describe his intelligence. "There's a little bit of a false rumor out there, so I just wanted to correct it, frankly".