A veteran jokingly told the US president that if “only he was 20 years younger” while pointing to the First Lady.
In the light-hearted moment following the D-Day 75 national commemoration, Donald Trump replied to 93-year-old Thomas Cuthbert: “You could handle it no question.”
Saying it was nice to meet him, the president added: “It’s my honour, believe me, thank you very much.”
After the reception, also attended by the Queen and the Prince of Wales, Mr Cuthbert, from Elmstead Market, Essex, said that Mr Trump “came across very well”.
He added: “He surprised me, when you see someone on the TV but he seemed different, he seemed one of the boys. His wife was very pleasant as well.”
Mr Cuthbert was awarded the Legion D’Honneur in May 2017 for his role in the D-Day landings during which he served on a landing barge oiler anchored off shore from Utah and Omaha beaches.
Charles served in the Royal Navy in the 1970s, ending his career commanding the minesweeper HMS Bronington and joked with Mr Cuthbert about suffering from sea sickness.
Referring to a segment of the commemorations that highlighted the conditions the men had to endure on the vessels heading to Normandy, the prince told Mr Cuthbert: “As they were saying the smell of the fuel and people being sick must have been terrible.
“I remember being in the navy and always being sick, and there was always someone who was never sick and would always appear with a mug of steaming soup.”
President Trump also wished happy birthday to Joan “Jonni” Berfield, a Wren, who worked as a coder and will be celebrating her 95th birthday on June 7.
When she told Mr Trump how old she was going to be, he replied, “You’re kidding”, and Mrs Trump said: “Nice to meet you. Happy birthday, hope you have a great celebration.”
When told of her role in the war, Mr Trump told her: “So you were well ahead of your time.
“Coder, that’s pretty sound, that means very smart. Great to meet you.”
And after talking to her about her involvement in D-Day, he added: “So you think back to that time. You can never forget it.”
Ms Berfield said after the meeting: “I was very surprised, he spoke very quietly, I wasn’t expecting that.
“He was very interested in what I had done, his wife was charming.
“I think I am in a dream and I will wake up and find it’s all a dream. It’s been a fantastic day, I’m just overwhelmed by everything.”
Royal Marine Douglas Chrome told the Queen how he had been an 18-year-old gunner on a landing craft on Juno Beach.
Mr Chrome, from Heathrow, west London, said: “I have never been back to Normandy and it will be the last.
“It was a real honour to meet the Her Majesty and then I saw Donald Trump. I had heard lots of things about him but he was actually very nice.
“He told me ‘we’re really proud of you’.”
Ted Cordery, 95, a leading seaman torpedoman on HMS Belfast, told the Queen how noisy it had been on D-Day.
He then spoke to President Trump and the First Lady.
“He said you guys did a great job but I said it wasn’t only us – your country did it as well,” Mr Cordery said.
“We shook hands and he said delighted to meet you. It has completely changed my mind of him.
“Eye-to-eye he is a really great guy. Honestly. Completely different to the impression I had before.
“I said we were all in it together.”
The president and First Lady then went on to a reception for US military and other special guests where he was thronged by service personnel seeking selfies.
Conservative MP Bill Cash also introduced himself to the president and said to him: “Congratulations Mr President. I’m a Conservative member of Parliament.”
Mr Trump said: “Good, you look like it. Who is going to be your next prime minister?”
Mr Cash replied: “I think it could be Boris, I am chairman of the European Committee in the House of Commons so congratulations, I’m a great fan.”
To which Mr Trump responded: “Give them my regards.”