Before leaving England, President Trump and first lady Melania Trump will sit down with Queen Elizabeth for their first official visit with the monarch. She has met with nearly every one of the last 12 presidents. Mr. Trump has said he is looking forward to meeting the queen, who he described as an "incredible woman," at Windsor Castle. Hordes of demonstrators converged in London on Friday morning, intent on mocking Mr. Trump on his only full day of business with British leaders on what has been dubbed a "working visit" to the United Kingdom.

In what has been a bumpy ride so far with the president slamming British Prime Minister in an interview with one of England's bestselling newspapers, this visit may come as welcome relief. The president has already expressed how they're looking forward to it and said the first lady is a tremendous fan.

In 66 years on the throne, the queen has seen nearly a dozen U.S. presidents come and go, reports CBS News' Charlie D'Agata. She's met them all with the exception of Lyndon Johnson. And while she and the current president may have different personalities, royal biographer Robert Hardman doesn't see a problem.

"They actually have quite a lot in common. They both got Scottish mothers, they both own fairly large parts of Scotland – in her case Balmoral in his case two golf courses – and she's used to dealing with the most appalling despots, monsters, crooks, dictators," Hardman said. "I think they're going to get on great."

One of the more memorable visits was that of John and Jacqueline Kennedy, just months after his inauguration in 1961. Some relationships have been warmer than others. Ronald Reagan became the first U.S. president to overnight at Windsor Castle, even horse riding with the queen.

"The Reagans, it was a really, really warm friendship. I mean once when the queen was in California with the royal yacht, it was the Reagans' wedding anniversary and she invited them around for a special wedding anniversary dinner and they all ended up around the piano singing," Hardman said.

Sing-a-longs aside, Mr. Trump and first lady Melania might be expected to follow protocol. As they're not British subjects, a bow and a curtsey isn't technically required, but appreciated. It's also polite not to turn your back to the queen. And even touching – can get a bit touchy.

"People always say you shouldn't touch the queen and, well you shouldn't really go around touching the queen. There's the famous story of Michelle Obama allegedly putting a hand around the queen what people forget is the queen actually put her hand around Michelle Obama," Hardman said.

In terms of protocol it is possible, even likely, that the queen will discuss work affairs. She is the head of state after all, but traditionally her views do not extend beyond those castle walls.