Amanda Holden rushed to her sister’s hospital bedside after she was involved in a horror car crash on Thursday morning.
The Britain’s Got Talent judge, 45, went straight to see Debbie Holden, 44, after learning of the accident.
Debbie is said to now be in a stable condition in the intensive care unit of a Cornwall hospital and is expected to make a full recovery.
“Amanda is in absolute agony. She’s very close to her sister,” a source said.
“She immediately travelled to Cornwall to be with Debbie.
They added to The Sun: “It’s been a very difficult 48 hours and the whole family have been pulling together and trying to keep positive.”
Britain’s Got Talent judge Amanda 45, had been a guest at Simon Cowell’s boozy 57th birthday bash in London on Wednesday night.
The sisters became close in adulthood after a fractured relationship with their father Frank as kids.
Their dad split from mum Judith in 1976 after six years of marriage on grounds of unreasonable behaviour due to his heavy drinking.
The pair became particularly close in 2012 when Amanda almost died through childbirth complications.
Last year, diving instructor Debbie, who is single and does not have children, narrowly escaped death when she was caught up in the Nepal earthquake which killed almost 9,000 people.
She miraculously missed being swept away by a 300-foot avalanche on Mount Everest, triggered by the 7.8 magnitude quake, because she had been struck down by altitude sickness.
Amanda later struggled to maintain her composure when she interviewed her sister live on ITV’s This Morning and Debbie revealed she had been caught in an aftershock.
When Debbie revealed there was no transport in her area, emotional Amanda shouted: “I love you!” Amanda admitted her family had been concerned about Debbie because she was an “outdoors type”.
Debbie has been travelling since leaving the UK in January 2000 “with a 50 litre backpack and very rough plan”, according to her blog.
Her work in deep sea diving and underwater photography now sees her split time between Cornwall and Koh Lanta in Thailand.
Amanda admitted her sister is a lot more of an ‘outdoors type’ than her and revealed she had saved up to climb Everest because it was her ‘dream’.
She said at the time: :She’s adventurous to say the least. She’d saved up and this was something she was desperate to do.”