"I have such a great relationship, and we were laughing and having fun. And her people said she hasn't had so much fun in 25 years. Then I got criticised for it because they said we were having too much fun," Trump said.
"On behalf of all Americans I offer a toast to the eternal friendship of our people, the vitality of our nations and to the long cherished and truly remarkable reign of her majesty, the queen," he declared at dinner with Queen Elizabeth II.
He later told Fox he thought she was an "incredible lady".
"I feel I know her so well and she certainly knows me very well right now, but we have a very good relationship also with the United Kingdom."
However Trump mistakenly cast the heir to the British throne, Prince Charles, as the "Prince of Whales".
"I meet and talk to 'foreign governments' every day. I just met with the Queen of England (UK), the Prince of Whales, the PM of the United Kingdom, the PM of Ireland, the President of France and the President of Poland," Trump wrote in a tweet, which was later deleted.
Despite protests during his UK visit, Trump maintains he had a great time.
In a separate tweet shared during his visit. he declared it was "going really well".
"The Queen and the entire Royal family have been fantastic. The relationship with the United Kingdom is very strong. Tremendous crowds of well wishers and people that love our Country," he wrote.
The Trumps have met The Queen before. Last year they visited Windsor Castle for tea.
BIRTHDAY SPAT
Trump's been busy speaking with the press on his birthday.
In another interview with ABC things got heated between him and Good Morning America anchor George Stephanopoulos when he was questioned about whether he ordered Special Council Robert Mueller to be fired following damaging testimony from former White House counsel Don McGahn's damaging testimony.
"The story on that very simply, No. 1, I was never going to fire Mueller. I never suggested firing Mueller," he said.
Stephanopoulos pressed him further about McGahn's testimony.
"I don't care what he says, it doesn't matter," Trump responded.
"Look, George, you're being a little wise guy, okay, which is typical for you. Just so you understand, very simple, it is very simple, there was no crime."