Prince Charles and Prince William are expected to meet President Donald Trump this week when he visits the United Kingdom with his entire family. However, there could be tension between the leaders.

Two years ago, the Sunday Times reported that Prince Charles and Prince William both refused to meet Trump when he visited the UK for work. A source told the publication that the royals both decided to snub the president of the United States.

“This business of Prince Charles and Prince William not being there for the Trump visit was a snub,” the source said. “They simply refused to attend. It’s a very, very unusual thing for the Queen to be there on her own. Usually, she is accompanied by somebody. Prince Charles has been substituting for Philip a lot recently,” the source added.

But despite the royals’ previous snub, Prince Charles is reportedly preparing to exchange views with Trump on some important issues. He is expected to meet the president this week, together with Prince William, Prince Harry and Kate Middleton.

Prince Harry’s wife, Meghan Markle, won’t be meeting Trump because she’s still on maternity leave. The Duchess of Sussex just gave birth to her son, Archie Harrison Mountbatten-Windsor, on May 6.

A source said that one of the topics that will be discussed during this week’s meeting would have to do with climate change. The insider said that the heir to the throne has been passionate about climate change for the past 40 years.

“And he will look forward to discussing it with the president should it come up,” the source said. “He would be very happy to have the opportunity to talk about it.”

In related news, Prince Charles also made headlines this week after it was revealed that he became increasingly concerned about Prince Harry while he was still in the Army. Duncan Larcombe, the author of “Prince Harry: The Inside Story,” said that the future king and Queen Elizabeth became wary of allowing Prince Harry to leave his military career in 2015. But in the end, Prince Charles and Her Majesty agreed that the decision to leave the Army is something that only Prince Harry could do.

Prince Charles and Prince William Prince Charles, Prince of Wales, in his role as a Royal Knight Companion of the Garter and Prince William, Duke of Cambridge, in his role as a Knight Companion walk in the procession to the Order of the Garter Service. WPA Pool/Getty Images