Princess Beatrice, 34, is known for wearing stylish dresses that not only look sophisticated, but show off her impressively toned legs.
SEE: Princess Beatrice's ethereal Self-Portrait dress was worn by another royal at Queen's funeral
The mother-of-one works hard to maintain her seriously sculpted muscles, regularly running to hone her calf muscles, which looked defined in her knee-length dress for her grandmother, Queen Elizabeth II's funeral.
WATCH: Princess Beatrice is a vision of grace for Queen's vigil at Westminster Hall
Beatrice has long been a keen runner, and is the only member of the royal family to have run the London Marathon, which she completed in 2010.
READ: Princesses Beatrice and Eugenie spark confusion at the Queen's funeral: Details
LOOK: Meghan Markle and Princess Beatrice twin at Queen's funeral - did you notice?
The 34-year-old was dedicated to her marathon training, with her trainer Nadiya Fairweather explaining: "We trained in snow, we trained in rain, we trained in mud, we trained in everything. She was committed."
Personal trainer David Wiener of workout app Freeletics sings the praises of running for toned legs, explaining: "Regardless of your body shape and size, runners tend to have powerful legs as they are constantly working the large muscles of their body."
Princess Beatrice has seriously toned calf muscles
Beatrice isn't the only royal who loves running. Princess Kate and Prince William are fans of the sport too.
LOOK: All the photos showing Princess Beatrice's close bond with her grandmother the Queen
Fellow royal sports enthusiast Mike Tindall, who is married to Beatrice's cousin Zara Tindall, revealed that the future king is a pro when it comes to sprinting.
Princess Beatrice runs to maintain her toned legs
"Willy's quick," Mike said. "I've raced him, he's quick, he has really fast leg speed." said Mike.
Mike Tindall has also commented on Princess Kate's running prowess, explaining: "She loves running, she can run all day. Engine!"
READ: Princess Beatrice and Edoardo Mapelli Mozzi's trailblazing wedding was so intimate – secret details
Despite both Prince William and Princess Kate being keen runners, they're unable to follow Princess Beatrice's lead and take part in the London Marathon.
When the Duchess was speaking to journalist Bryony Gordon, she was asked if she would be running the London Marathon, to which Duchess Kate replied: "Oh no, security and all that."
Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity and royal news delivered directly to your inbox.