The pop group – also including Cheryl, Nicola Roberts and Kimberley Walsh – had been planning to reunite for their 20th anniversary next year, but will now focus their attention on supporting Harding through her illness.
Speaking to The Sun‘s Bizarre column, Coyle said: “I would love to be like, ‘Yes, this is what we’re doing’. At the minute, it’s very much thinking about Sarah, being there for Sarah.
“It’s a really unfortunate time for her and the whole thing is like, ‘Come on, come on’, because then that could be the priority – talking about, ‘Should we do a tour? Should we do something?’ Instead we’re worried about Sarah.
“We’re just focusing everything there. That is the main priority.”
Harding was diagnosed with breast cancer last year and shared the news with fans in August, at which point the disease had spread to other parts of her body.
The 39-year-old singer has been working on a book, titled Hear Me Out, and yesterday (March 13) shared an extract, published by The Times, in which she said that doctors have told her Christmas 2020 “would probably be [her] last.”
In a foreword interview, Harding said she had had a mastectomy and chemotherapy and was being looked after by her mother. “Nothing is certain any more,” she said. “I’m just grateful to wake up every day and live my best life because now I know just how precious it is.”
In the excerpt, Harding explained that “for a while, it seemed like the chemo was working,” but that a later MRI scan had revealed another tumour – “either at the base of my spine or on my brain”. A second MRI revealed another tumour.
The star joined Girls Aloud during their initial creation on the reality show Popstars: The Rivals in 2002, and continued to perform with them until they broke up in 2013.