Phoebe Gates and Arthur Alistair Donald are officially dating.

Over the weekend, the 21-year-old daughter of Bill and Melinda Gates shared her Stanford University graduation photo diary on Nylon. In one of the photos, she referred to Paul McCartney's 25-year-old grandson as "my boyfriend."

In the 1 p.m. segment of her photo diary, she attached a snap of Arthur giving her a piggyback ride and captioned it: "My boyfriend, Arthur, giving me a lift post-ceremony."

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Later that day, at 6:26 p.m., she shared another photo of them hugging in matching blue outfits and wrote, "With Arthur, he cleans up nicely."

It wasn't the first time the Bachelor of Science in Human Biology graduate talked about her beau on social media. In October 2023, she took to Instagram to share a picture of them in Paris.

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Her post drew curiosity from her followers and social media users at the time because she was known to be dating a Black guy.

Phoebe's first photo with Arthur came around ten months after she posted a romantic compilation video of her and her ex on her TikTok account.

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Aside from curiosity-filled comments, her Paris snap with Arthur received a remark, saying, "Prayers for my young brother who fumbled a bag of the century."

Another user responded to the comment, writing, "He got his own bag. LMAO. Dude wouldn't have been able to get anywhere near her if he didn't have his own connections and money."

Paul McCartney
In this image released on May 3, Sir Paul McCartney visits Paul McCartney Photographs 1963-64: Eyes of the Storm at Brooklyn Museum on April 29, 2024 in Brooklyn, New York.
(Photo : Theo Wargo/Getty Images for MPL)
True enough, Arthur is the grandson of "Britain's first billionaire musician." Per Fox Business, his Beatles legend grandfather is estimated to be worth 1 billion pounds or U.S.$1.27 billion.

The English singer-songwriter is also reportedly the first Beatles member to become a billionaire.

Bill Gates
Philanthropist and former Microsoft CEO Bill Gates speaks in a panel discussion at the Global Solutions Summit on May 07, 2024 in Berlin, Germany. The Global Solutions Summit brings together people from all over the world to discuss pressing global policy issues.
(Photo : Sean Gallup/Getty Images)
Bill Gates, on the other hand, has a real-time net worth of US$134.1 billion as of Wednesday, according to Forbes. As of press time, the Microsoft co-founder is the 9th richest billionaire on Forbes' real-time billionaires list.

Phoebe is Bill's youngest child with his ex-wife Melinda, while Arthur is the eldest son of Paul and Linda's daughter Mary Anna with ex-husband Alistair Donald.