Princesses Beatrice and Eugenie Pose for Rare Sister Photo as Royal Family Health Crisis Continues

Princess Beatrice and Princess Eugenie posed together in a rare sister moment while supporting musician Ellie Gouldingat a recent event.

The Princesses of York attended the singer's SERVED Private Party at Royal Albert Hall in London on Thursday, April 11. Beatrice, 35, wore a green skirt paired with a black jacket and bejeweled flats. Eugenie, 34, kept it simple in a gray sweater dress as she posed alongside her sister.

Beatrice also made the event a date night as she was spotted with husband Edoardo Mapelli Mozzi. The couple snapped some photos with the event's host, Goulding. Eugenie's husband, Jack Brooksbank, didn't appear to be in attendance.

Both Beatrice and Eugenie have been spotted more frequently in the public eye as the royal family faces a series of health scares .

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Both King Charles IIIand Princess Kate Middletonare undergoing treatment following their respective cancer diagnoses. Charles, 75, went public with his health news in February , after a routine prostate procedure. Kate, 42, revealed her illness in a video late last month, revealing that the cancer was discovered during an abdominal surgery earlier this year.

As news of the royal family's health crisis continued to make headlines, Eugenie posted a pretty pointed message on social media, revealing that she's "cherishing family and loved ones," in a March Instagram post.

Beatrice, meanwhile, has impressed higher-ranking members of the royal family as she's stepped up during Charles and Kate's ongoing health battles. Various U.K. outlets have reported that a more senior role within the family could be in her future.

Royal historian Gareth Russellweighed in on Beatrice's possible promotion during a recent interview with Us Weekly , explaining that the monarchy will be "unsustainable" if there are no new senior working royals.

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"At the minute, Prince Williamis the only senior working royal man under the age of 60 and above the age of 16," Russell explained, speculating that Beatrice, Eugenie and Lady Louise Windsor's roles in the family could be changed.

Before his reign, Charles revealed his plan to have a slimmed-down monarchy once he took the throne. However, what's going on within the family currently is "not what was intended," Russell told Us .

"If you are to use the metaphor, the monarchy is underweight at this stage, it was never intended to reach the levels that it did," he added. "It was always anticipated that you would have [King] Charles III with three working siblings and two working children and their wives, and that that would be a sustainable footing for the monarchy going forward."