Zara Tindall was deeply distressed by Princess Anne's recent injuries, which resulted in the royal spending five nights in the hospital, sources claim.
The accident, where the Princess Royal was struck by a horse at her Gloucestershire estate last week, left her daughter worried and deeply shaken.
After many years of concern for her mother's well-being, the incident has had a profound impact on Zara, aged 43. Princess Anne's husband, Vice Admiral Sir Timothy Laurence, has expressed gratitude to the medical staff at Southmead Hospital who cared for her.
Sir Timothy confirmed that Anne is slowly recovering from the accident. Despite this, Zara continues to be concerned about her mother's condition, according to a source.
A source claimed: "This is exactly what Zara's been worried about happening for years now, but her mum hasn't had a chance to slow down with everyone else falling apart.
"It's really shaken Zara to the core and she's desperately hoping this memory is temporary."
The source continued to tell Woman's Day Magazine: "This has been a huge wake-up call for everyone in the family and they're rightfully distressed."
Zara was seen visiting her mother in hospital shortly after the incident became public news.
The sister of King Charles will now rest at home and follow standard concussion protocols, according to reports.
She is expected to return to public duties when doctors advise that it's safe to do so.
Princess Anne's incident happened before King Charles hosted the Emperor and Empress of Japan at Buckingham Palace as part of a three-day State Visit.
It is not the first time the late Queen Elizabeth II's daughter has suffered from a horse-related incident.
In 1976, during the Olympics in Montreal, her horse Goodwill failed to make one of the jumps on the course which caused her to fall.
In 2008, Princess Anne was spotted using a walking stick after being kicked by a horse at her home.