Prince William and Kate Middleton
Prince WIlliam, Kate Middleton stayed at Princess Diana's favorite hotel on their first trip to New York City. Pictured: Prince William and Middleton sit in front of the Taj Mahal during day seven of the royal tour of India and Bhutan on April 16, 2016 in Agra, India. Getty Images/Ian Vogler

Kate Middleton and Prince William remembered Princess Diana during their first visit to New York City.

In the upcoming documentary "Always at the Carlyle," hotel staff and royal experts shared how the Duke and Duchess of Cambridge's inaugural visit to the Big Apple in 2014 went. According to them, Prince William and Middleton opted to stay at Princess Diana's favorite hotel.

"The duke and duchess I think definitely stayed here at the Carlyle because Princess Diana used to stay here and she was very fond of this hotel," said Jennifer Cooke, director of communications at The Carlyle (via People).

"I know that they had heard about it," she added. "I heard him say that in the lobby that he had heard so much about this hotel through the years and they were really happy to be here."

Piers Morgan was among the reporters on hand at the hotel when Prince William and Middleton arrived. He recalled what he observed on that day. "I saw them arriving and it was an amazing moment because New Yorkers, in particular, tend to be very sanguine about the royals until they're actually near them, and then like everybody else in the world they go completely bonkers," he recalled.

"Always at The Carlyle" will take the audience inside the walls of the popular hotel. It will also explore the untold stories and secrets of the building. The film will hit theaters in early 2018.

In related news, Prince William and Middleton welcomed their third child, Prince Louis, on April 23. It took four days for the palace to announce the newborn's name, which was unusual as they disclosed Prince George and Princess Charlotte's just two days after their births.

According to reports, the delay was due to Prince Charles not being able to meet his newest grandson right away as he was in Scotland for a royal engagement. The Prince of Wales met Prince Louis when he visited the family of five on Princess Charlotte's birthday on Wednesday.

In related news, royal fans were initially confused as to how to pronounce Prince Louis' name properly. They were torn between reading it as "Loo-wee" or "Loo-wis." However, Middleton was heard mentioning the name during her royal wedding to Prince William, whose complete name is William Arthur Philip Louis, and she used the former pronunciation.