Princess Eugenie and Princess Beatrice
Princess Eugenie is likely to choose her sister, Princess Beatrice, as her maid of honor. Pictured: Princess Beatrice and Princess Eugenie pose next to a Mini in front of Brandenburg Gate as they promote the GREAT initiative on Jan. 17, 2013 in Berlin. Getty Images/Chris Jackson

Princess Eugenie is likely to choose her royal sister, Princess Beatrice, as her maid of honor at her royal wedding.

Sarah Ferguson and Prince Andrew's youngest daughter is the next royal bride after Meghan Markle. According to Daily Express reporter Francesca Specter, just like Kate Middleton, Princess Eugenie might also opt for her sister to be her maid of honor.

It is customary for royal brides to choose one adult woman in their wedding party along with younger bridesmaids or flower girls. The Duchess of Sussex opted to not follow this rule as she has "a very close-knit circle of friends and she didn't want to choose one over another." But Middleton sticks to the protocol by making her sister, Pippa, as her maid of honor.

Specter believes that Princess Eugenie will follow Middleton's choice considering her close bond with her sister. Princess Eugenie and Princess Beatrice are only a year apart in age. They have previously lived together at an apartment in St. James' Palace and maintain a close sibling bond.

In March, the royal sisters supported the star-studded WE Movement. At the event, Princess Eugenie shared her scoliosis diagnosis and how her big sister helped her during those difficult times.

According to the next royal bride, her condition "could have impacted my life and stopped me from doing the things I love." But Princess Beatrice was there to encourage whenever she was disheartened. Her older sister was there for her "no matter what."

"You encouraged me not to get disheartened. Not to give up. To live fearlessly," Princess Eugenie said of Princess Beatrice. "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."

Princess Eugenie is marrying her fiancé, Jack Brooksbank, on Oct. 12 at St. George's Chapel at Windsor Castle, where Prince Harry and Markle tied the knot. Her mom, Ferguson, is expected to help her with the wedding preparations.

"I am sure that as with all mothers of the bride, Sarah Duchess of York will be assisting her daughter with all aspects of the wedding especially when it comes to picking the wedding dress," former royal butler Grant Harrold said. "This is an important time for any bride and I have no doubt Princess Eugenie will be getting guidance from her mother while planning this special day."