It's been nearly four months since Archie Lyndhurst passed away tragically at the age of 19. The young actor's death on Sept. 22, 2020, came as devastating news to all, and it's a loss that his mother has called "totally irreparable."

Archie was the only son of Lucy Lyndhurst and actor Nicholas Lyndhurst, and his mother has now written a tribute to her late son, in which she honoured his memory and revealed what caused his death.

Archie Lyndhurst died of intracerebral haemorrhage (ICH)

In a two-post message on Instagram, Lucy remembered her son and explained that he died of a rare disease—which showed no signs—and that nothing could have been done to prevent his death. She wrote:

"Four days before Christmas Nick and I sat in Harley Street with the results of Archie's second post mortem. A very detailed document, which we had been warned by the coroner would be a harrowing read, and best explained by a medical practitioner.

"The Dr explained Archie died from natural causes (something we knew already, only gossips, keyboard warriors, trolls and the ignorant thought differently)," she continued. "He died from an Intracerebral Haemorrhage caused by Acute Lymphoblastic Lymphoma/Leukaemia. This is not Leukaemia as we know it, the word Acute in medical terms means rapid. 

"He assured us that there wasn't anything anyone could have done as Archie showed no signs of illness. Archie had numerous bleeds on the brain and the Dr went to great lengths to reassure us that he wouldn’t have been in any pain as it happened in his sleep. The results utterly floored us to think something like this could happen. It's very rare and around only 800 people a year die from it."

Lucy continued, "Only days before he'd been with the love of his life Nethra celebrating his birthday early as she was due to go away with work commitments. Life is fragile, precious and sometimes incredibly cruel."

Archie Lyndhurst (2001-2020)

Lyndhurst's death at the age of 19 came as heartbreaking news in late 2020. The young actor had starred on CBBC's So Awkward and had a promising future ahead of him.

Archie Lyndhurst

"Archie was an empath," his mother wrote in her Instagram post. "He loved life, he valued everyone in it and every moment he was given. He was always singing, and had such energy and passion in everything he did. To be part of his life has been the biggest joy mad honour. We miss him everyday and always will."