"Today as sisters we stand here to support not only each other but all women," Beatrice said at the 2018 We Day U.K. Charity Concert

Princess Eugenie is paying tribute to her big sister Princess Beatrice.

The royal cousins of Prince William and Prince Harry – who are the daughters of Prince Andrew and Sarah Ferguson, the Duke and Duchess of York – spoke to fans at the 2018 We Day U.K. Charity Concert on Wednesday, during which the newly engaged Eugenie shared a heartwarming tribute to her older sibling.

“As my big sister, you inspire me. I love that, as a team, we work hard to support each other – no matter what,” the 27-year-old shared.

“When I was 12 I was diagnosed with, and treated for, scoliosis and I have lived with two 12-inch metal rods in my back. It could have impacted my life and stopped me from doing the things I love,” said Queen Elizabeth‘s granddaughter, who got engaged to longtime boyfriend Jack Brooksbank in January after dating for seven years.

Scoliosis is a medical condition in which a person’s spine has a sideways curve.

“You encouraged me not to get disheartened. Not to give up. To live fearlessly. Today, I am so lucky to get to work with and support other young women who are going through the same thing. To encourage them to not let their diagnosis win. To live fearlessly too,” the bride-to-be shared.

Princess Beatrice and Princess Eugenie
| Credit: Isabel Infantes/PA Images/INSTAR

“Today as sisters we stand here to support not only each other but all women,” Beatrice, 29, also told the crowd.

In April 2012, Eugenie detailed her health battle to support the Royal National Orthopaedic Hospital.

“I can still vividly remember how nervous I felt in the days and weeks before the operation,” she recalled. “During my operation, which took eight hours, my surgeons inserted eight-inch titanium rods into each side of my spine and one-and-a-half inch screws at the top of my neck. After three days in intensive care, I spent a week on a ward and six days in a wheelchair, but I was walking again after that.”

Without the operation, Eugenie said, “My back would be hunched over.”

Adding: “My back problems were a huge part of my life, as they would be for any 12-year-old. Children can look at me now and know that the operation works. I’m living proof.”

Nearly two decades after her procedure, Eugenie continues to advocate for the London clinic that treated her and speaks out about anxieties faced by children when they have to be hospitalized.

WATCH: Princess Eugenie Shows Off Sapphire Engagement Ring (with Major Kate Vibes!)

And soon, she will tie the knot with her wedding to be held October 12 at St. George’s Chapel, Windsor Castle, five months after Prince Harry and Meghan Markle marry at the very same venue on May 19.

A friend of the princess previously told PEOPLE that there is “zero competition” among Eugenie and Jack and Harry and Meghan. “It is complete love, and there is room for all of them,” the friend explained.