Fans of the British royal family have always been intrigued by everything surrounding the members' fashion, ranging from what they are not allowed to wear before 6 p.m. to the subtle messages they send with various style choices.

Now, Angela Kelly, Queen Elizabeth II's personal assistant, has shed some light on what goes on behind the scenes when the monarch chooses what she will wear for her Christmas Day speech every year.

According to The Sun, Kelly shared that Her Majesty will never wear red or green to the event for "a very good reason." As included in her 2019 tell-all, "The Other Side of the Coin: The Queen, the Dresser, and the Wardrobe," Kelly revealed that the royal stays away from the bold colors due to the fact that they may clash with the tree or not show up well on camera.

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As for how the stylist decides what outfit will be chosen, Kelly stated that she first gets all of the details from the broadcasters about the set and goes from there as she begins coming up with a range of options. The process, which takes place weeks before the Queen's actual appearance, is also multi-layered.

"Firstly, I ask what colours and decorations they're planning to use for the scene and they'll give me a detailed description, including which furniture will be featured and how the tree will be decorated," she said, adding that she then will pick out a "selection of outfits" for Her Majesty "based on the colours chosen for the setting."

In previous years, the Queen has worn an assortment of colors, such as lilac, ivory, and peach, which go against the bright outfits that the royal typically wears.

The monarch is not the only member of the royal family whose use of color in clothing has been discussed in recent months. Earlier this year, Duchess Meghan Markle and Duchess Kate Middleton strategically wore a similar shade on their royal tours that caught the attention of many.

Queen Elizabeth II
Queen Elizabeth II attends a Christmas Day church service at Sandringham on Dec. 25, 2015 in King's Lynn, England. Getty Images/Chris Jackson