Upham was one of two swimmers who went missing during an annual Christmas Day swim in Devon, England.
On Sunday, Dec. 28, the English singer paid tribute to Matthew Upham, who died on Christmas Day in a swimming incident in Budleigh Salterton beach off the coast of Devon, England. Upham, 63, was an antiques dealer.
In a statement posted to her website, Bush wrote, "As you might have heard on the news. Matthew Upham was one of the swimmers who went missing in the sea in Devon on Christmas Day. Matthew was one of my very dearest friends. I'd known him for thirty years."
"He was one of those people who touched everyone he met. He was extraordinarily kind, thoughtful and lived life to the full. He was also a great deal of fun," she continued. "His family are heartbroken and along with many of his friends, so am I."
"Matthew was a very strong swimmer. He had a great love for kayaking. He understood the sea should be respected. It's so tragic that he lost his life this way," continued the "Running Up That Hill" artist.
Bush ended her tribute by saying, "The world has lost someone incredibly special. Thank you, Matthew, for being one of the best friends anyone could have."
On the morning of Dec. 25, BBC reported police were called as two people were reported missing after a group of swimmers experienced difficulty in the water during an annual Christmas Day at Budleigh Salterton beach.
Authorities confirmed "a number of people were safely recovered to shore and checked either by paramedics at the scene or taken to hospital as a precaution." A search operation was in place to find the two men but called off later that evening, according to BBC.
Upham's family paid tribute to Matthew on his Instagram page, Matthew Upham Antiques.
"Our family is heartbroken by the loss of our beloved Matthew Upham, who was reported missing on Christmas Morning," the statement read. "Matthew is deeply loved and will be forever missed."
"We would like to express our sincere and heartfelt thanks to the emergency services who responded, particularly the RNLI and coastguard, for their dedication, professionalism, and tireless efforts during this extremely difficult time. We are profoundly grateful for the compassion and support."
"As we grieve and support one another, we kindly ask that our family's privacy is respected," the statement continued. "We thank everyone for their understanding, kindness, and condolences."