President Trump took to Twitter Sunday to congratulate Princess Eugenie on her marriage to Jack Brooksbank.

“Princess Eugenie of York was a truly beautiful bride yesterday. She has been through so much, and has come out a total winner!” Trump tweeted about the royal newlywed, although her wedding occurred on Friday, not Saturday.

Trump was most likely referring to Eugenie’s battle with scoliosis when she was a child. The daughter of Prince Andrew, Duke of York, and Sarah Ferguson underwent surgery when she was 12 years old to treat the condition. The operation left a scar down her back, which she showed off with her low back wedding dress and no veil.

PRINCESS EUGENIE AND JACK BROOKSBANK'S ROYAL WEDDING RECEPTION DETAILS REVEALED

Eugenie requested a dress that displayed the scar to draw awareness to the condition.

“The low back feature on the dress was at the specific request of Princess Eugenie who had surgery aged 12 to correct scoliosis,” the palace said in its official statement.

Princess Eugenie of York shows off her scar in her wedding dress on Friday, Oct. 12, 2018. (AP)

Eugenie tied the knot to her longtime boyfriend on Friday in front of hundreds of guests at St. George’s Chapel in Windsor Castle. The ceremony was followed by the traditional carriage ride through the streets of Windsor and a lunch celebration at St. George's Hall Grand Reception Room hosted by Queen Elizabeth for the couple’s 800 guests.

Prince Harry and Meghan Markle also had their royal wedding at St. George’s Chapel in May.

Trump and first lady Melania Trump made a charity donation as a wedding gift to Duke and Duchess of Sussex, but did not publicly congratulate them on social media.

Fox News' Morgan Evans contributed to this report.