Donald Trump wished Meghan Markle well in her new life as a British royal

U.S. President Donald Trump said Britain's Prince Harry was a terrific guy and denied casting his American-born wife, Meghan, as a nasty person, claiming media had distorted his words as he actually felt she was very nice.

He also said he had a long discussion about climate change with heir-to-the-throne Prince Charles, although Trump suggested he did not believe the Earth is getting hotter, but that "it changes both ways".

Trump is on a pomp-laden state visit to Britain and has been feted by the royal family and Britain's political elite. Trump met Queen Elizabeth and Prince Charles on Monday and was treated to a banquet at Buckingham Palace.

Hollywood actress Meghan Markle, now the Duchess of Sussex, married Charles's younger son Harry last year and gave birth to their first child, Archie, last month. She criticised Trump during his 2016 election campaign as misogynistic and divisive.

Before arriving in Britain, Trump, on being told of Meghan's criticism of him by The Sun newspaper, said: "I didn't know that. What can I say? I didn't know that she was nasty." But he also wished her well in her new life as a British royal.

Speaking to ITV in an interview aired on Wednesday, Trump clarified the comments saying that he had been referring specifically to Meghan being nasty to him and that he thought she was very nice.

"I said: 'well I didn't know she was nasty' - I wasn't referring to she's nasty, I said 'she was nasty about me'," Trump told ITV. "And essentially, I didn't know she was nasty about me. So I said 'but you know what: she's doing a good job - I hope she enjoys her life'.

"I think she is very nice. Honestly I don't know her. So I have to be honest - I don't know her," Trump told ITV. "She was nasty to me. And that's OK for her to be nasty. It's not good for me to be nasty to her and I wasn't."

Trump said that he had met Prince Harry during the visit: "I did. I did. I congratulated him and I think he's a terrific guy. The royal family is really nice."

"I think he is great," Trump said of Harry.

During the visit, Trump had tea with Charles, who has campaigned for years to raise awareness about the destruction of the environment and the impact of climate change.

"We were going to have a 15-minute chat and it turned out to be an hour-and-a-half and he did most of the talking - and he is really into climate change and I think that's great," Trump said. "I totally listened to him. And he also talked about architecture.

"He wants to make sure future generations have climate that is good climate as opposed to a disaster - and I agree. I did mention a couple of things: I did say, well, the United States right now has among the cleanest climates there are based all the statistics, and it's even getting better.

"I agree with that: I want the best water, the cleanest water, crystal clean," he said.

When asked if he believed in climate change, Trump said:

"I believe that there is a change in weather and I think it changes both ways. Don't forget it used to be called global warming, that wasn't working, then it was called climate change and now it is actually called extreme weather - because with extreme weather you can't miss."