Sarah Harding devastatingly lost her battle to breast cancer this week at the age of 39.
She had bravely opened up about her battle last year, explaining how she had been diagnosed with breast cancer, which later spread to her spine.
But her case was very "unusual", according to GMB regular Dr Hillary, who has explained how most women who die from breast cancer or develop it are usually in their 60s and 70s.
"We hear a lot about breast cancer in younger women because it’s so shocking when it happens, but about five per cent of breast cancer is found in under 40s, and very, very rare in 20s," he said on Good Morning Britain.
"39 is still very young; the majority of women who die from breast cancer or develop breast cancer are 60s and 70s and beyond, so this is an unusual case.
"But when it is diagnosed in younger women, it tends to be later stage and more aggressive."
He explained how it had been very "unlucky" that Sarah's diagnosis came at a time where services were delayed due to the coronavirus pandemic.
He added: "It was very unlucky. It couldn’t have been worse timing right then, when we approached the first lockdown and services were being postponed."
Dr Hillary had once interviewed Sarah, standing in for Richard Arnold, and he described the late singer as a "wonderful, vivacious, happy, bubbly, cheeky girl".
"What a wonderful interview, and what a change to what I normally do, and Sarah was a wonderful, vivacious, happy, bubbly, cheeky girl, and it’s just a tragedy at the age of 39," he said.
Sarah's passing was confirmed by her devastated mother Marie.
"It’s with deep heartbreak that today I’m sharing the news that my beautiful daughter Sarah has sadly passed away," she started a statement, posted on Sarah's Instagram account.
"Many of you will know of Sarah’s battle with cancer and that she fought so strongly from her diagnosis until her last day.
"She slipped away peacefully this morning.
"I’d like to thank everyone for their kind support over the past year."
Marie went on to explain how she hoped Sarah would always be remembered for being a "bright shining star".
"It meant the world to Sarah and it gave her great strength and comfort to know she was loved," she added.
"I know she won’t want to be remembered for her fight against this terrible disease - she was a bright shining star and I hope that’s how she can be remembered instead."
