Harding’s mother Marie announced that the Girls Aloud singer had died on Sunday morning, describing her daughter as a ‘bright shining star’.
Celebrities across the globe have shared their condolences following the news, with Holly and Phil being the latest presenters to pay their respects on today’s episode of the ITV programme.
‘It’s a tragic loss of a wonderful, wonderful woman, who fought that battle bravely and publicly as well. This is a sad loss.
‘Our greatest condolences to her family and to her friends.’
Echoing a similar sentiment, Holly added: ‘Really sad.’
Harding revealed last August that she had been diagnosed with breast cancer, which had spread to other parts of her body.
Earlier this year, she said she was told by a doctor she will probably not be alive next Christmas.
In an extract of her memoir, titled Hear Me Out, which was published in The Times, Harding wrote: ‘I don’t want an exact prognosis. I don’t know why anyone would want that. Comfort and being as pain-free as possible is what’s important to me now.’
She added that she was trying to ‘live and enjoy every second of my life, however long it might be’.
‘I am having a glass of wine or two during all this, because it helps me relax,’ the singer continued.‘I’m sure some people might think that’s not a great idea, but I want to try to enjoy myself. I’m at a stage now where I don’t know how many months I have left.
‘Who knows, maybe I’ll surprise everyone, but that’s how I’m looking at things.’
Girls Aloud star Nicola Roberts shared a series of photos of her and Harding together and wrote: ‘I’m absolutely devastated and I can’t accept that this day has come. My heart is aching and all day everything we went through together has raced round my mind.
‘Especially this last year since her diagnosis, as hard as the year has been, our new memories are strong in my heart.
‘There are so many things to say and at first it felt to personal to put them here and then I remembered that there are so many other people grieving her too.
‘A part of me or us isn’t here anymore and it’s unthinkable and painful and utterly cruel. She would have loved your messages today.’
Nicola described her bandmate as ‘Electric girl’ and added: ‘You gave it everything and still with a smile.
‘A white butterfly flew past my window this morning before I knew, it must have been you.’
This Morning airs weekdays at 10am on ITV.