Matt's sister Carys Bray took to Instagram.com to post a photo of Harry alongside her daughter Alice, but the pop star's short hairdo became the center of attention as the picture made its rounds online, since the snap was the first clear photo of Harry's new look since he cut off his long locks earlier this month (May16).
Carys later took down the photo and subsequently made her account private.
It is unclear if Matt's other celebrity friends were in attendance.
Matt was found dead on Friday, and his family confirmed the beloved photographer had committed suicide, releasing a statement which read: "We are tremendously proud of Matt. He pursued his goals with passion, enthusiasm and warm-heartedness. We are devastated that he took his own life.
"Matt was extremely talented, but he was also kind and generous; an extraordinary, beautiful man who will be terribly missed by us, and by his many friends."
After news of his death surfaced, many stars who worked with Matt took to social media to pay tribute to their friend, including Harry's bandmate Niall Horan, who was among the first of Matt's famous friends to remember him by posting a photo of the pair on Instagram.com with the touching caption, "Rest well Matt. Can't believe I'm (sic) writing this. Incredible person."
Nicki Minaj, Rita Ora and British fashion designer, presenter and model Alexa Chung also honored the late photographer on social media.