Princess Eugenie
Princess Eugenies has started planning for her royal wedding with Jack Brooksbank. Pictured: Princess Eugenie and Brooksbanks pose in the Picture Gallery at Buckingham Palace after they announced their engagement on Jan. 22, 2018. Getty Images/Jonathan Brady

Princess Eugenie is already gearing up for her wedding with fiancé Jack Brooksbank.

On Thursday, Prince Harry's cousin took to Instagram to share a throwback photo. In the snap, Princess Eugenie is wearing a white gown. She seems to be one of the bridesmaids in a royal wedding, which she did not talk about in the caption. "90s throwback...wedding planning starts!!" she wrote.

Princess Eugenie's followers were quick to respond to her post, with some expressing their excitement and support. The majority cheered on the bride-to-be by leaving sweet messages in the comments section.

"The world can't wait!!!" trisarahtops1228 wrote.

"So exciting! Thanks for sharing," jdkarriker agreed.

"Looking forward to your wedding day, you will be a gorgeous bride!" allisondolfay added.

"Can't wait to see your beautiful dress! This is such a special time. Enjoy!!" another user wrote.

"@princesseugenie great pic. I love the children as attendants. If you use adult friends, I guarantee you, there will be a fight," hrhlyndagears commented.

According to royal expert Marlene Koenig, the royals prefer youngsters as their wedding attendants. "If you look at the royal weddings since [Queen] Elizabeth's, you will find that most of the bridesmaids are early teens or children," Koenig told Town & Country.

In fact, there are rumors that Prince George and Princess Charlotte are part of Prince Harry and Meghan Markle's royal wedding. Jessica Mulroney's daughter, Ivy, is also rumored to be part of the entourage.

Princess Eugenie has not released new updates about her wedding, including who will be her attendants. However, the couple has already confirmed that their wedding ceremony will be held at St. George's Chapel, where Prince Harry and Markle are also tying the knot this May.

Four days ago, Princess Eugenie shared another throwback photo on her social media account to honor her mom on U.K.'s Mother's Day. The snap featured Sarah Ferguson and her sister, Princess Beatrice.

Ferguson is very proud of Princess Beatrice and Princess Eugenie's contributions to the charity they supported. Earlier this month, the two princesses joined the WE movement. During the event, Princess Eugenie opened up about her scoliosis battle and shared how her sister helped her recover.

"Leading by example of unity and confidence, well done @yorkiebea and Eugenie @WEMovement #WeDayUk #weday," Ferguson wrote on Twitter, while tagging her two daughters.