Queen Elizabeth is making a bold statement as she marks 70 years on the throne.

On Sunday, the reigning monarch was spotted applying her hot pink lipstick from a gold tube while watching the Platinum Jubilee Celebration at The Royal Windsor Horse Show at Windsor Castle. On Friday, the queen was all smiles – while rocking the same shade – as she admired her horse, Balmoral Leia, from her Range Rover.

Last month, Elizabeth opted for the same look as she sported the lipstick while driving around her Sandringham estate on her birthday.

The queen's exact shade has been kept top secret for decades. However, the monarch’s senior dresser and in-house designer, Angela Kelly, previously revealed that Elizabeth Arden has held a Royal Warrant for nearly 60 years. The queen is reportedly a fan of the brand’s Beautiful Color Moisturizing Lipstick. A fuchsia shade named "Raspberry" seems to match the color Elizabeth tends to go for. "Pink Punch," a warmer shade, is another possibility.

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Queen Elizabeth Lipstick

Queen Elizabeth II's lipstick has been kept top secret over the years. (MEGA)

Elizabeth is also known for wearing a pale pink hue, which seems to be similar to Elizabeth Arden’s Rose Petal, a classic lipstick. For previous engagements, eagle-eyed style experts have suspected that the monarch wore Elizabeth Arden’s Exceptional Lipstick, known for its vibrant shades and creamy textures. It has since been discontinued.

But Elizabeth Arden isn’t the only brand with a Royal Warrant, which means that goods are provided to the sovereign or a member of the royal family. Clarins also has a Royal Warrant and was reportedly commissioned by the queen to create a red lipstick for her to wear on her Coronation Day in 1953. The shade was not only made to match her ceremonial robes, but it was also meant to last as the ceremony was about three hours long.

Sally Bedell Smith, a royal expert and author of "Elizabeth the Queen: The Woman Behind the Throne," wrote that Elizabeth always has lipstick in her purse. And while the queen carries a compact mirror, she has been seen in recent years reapplying without one in public.

"At the end of a luncheon or a dinner, even a banquet set with silver gilt and antique porcelain, she has the somewhat outré habit of opening her bag, pulling out a compact and reapplying her lipstick," she wrote.

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Queen Elizabeth coronation

Queen Elizabeth II in her coronation crown, 1953. (Hulton Archive/Getty Images)

Elizabeth's appearance on Friday was the first time she has been seen in public since attending the Service of Thanksgiving honoring her late husband in March. The Windsor Horse Show is one of her favorite annual events and she typically attends.

Last Tuesday, the queen missed the State Opening of Parliament due to "episodic mobility problems." Prince Charles went on to deliver the Queen’s Speech for the first time. The queen’s decision to delegate her role to Charles is likely to be seen by the public as evidence that a transition is underway, with the monarch remaining on the throne but turning over more responsibilities to her eldest son.

She has only missed the speech twice before. The first time was in 1959, during the late stages of her pregnancy with Prince Andrew, and the second was in 1963 before Prince Edward’s birth. On both occasions, Parliament was opened by a royal commission, with the speech delivered by the presiding member.

Buckingham Palace didn’t elaborate on what it called "episodic mobility problems,″ but the queen has had difficulty moving around in recent months. She has been seen using a cane on some occasions and Andrew escorted her into Westminster Abbey for the memorial service for Philip.

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Queen Elizabeth Platinum Jubilee

Queen Elizabeth II departs her official platinum jubilee celebration "A Gallop Through History" performance at the Royal Windsor Horse Show at Home Park on May 15, 2022, in Windsor, England. (Chris Jackson/Getty Images)

Elizabeth, who only recently recovered from a bout of COVID-19, is also preparing for four days of festivities celebrating her Platinum Jubilee that are scheduled for June 2-5.

The Associated Press contributed to this report.