Cheryl Cole said she "lost it" after Sarah Harding revealed her heartbreaking cancer update on FaceTime.
While Cheryl had intended to offer a listening ear to her Girls Aloud bandmate, she was instead overcome by her emotions upon hearing Sarah's "terrible" update, The Mirror reports.
In an excerpt from Sarah's new book Hear Me Out, published in The Times, Cheryl wrote: "Mostly, I try to keep my own emotions in check, but on one FaceTime call with her the other day, I couldn't hold it in. She relayed some terrible news, and I lost it and started crying."
She said she tried to move the phone out of the way so Sarah couldn't see her face as she sobbed.
Showing her own strength, Sarah then stepped in to comfort her friend, with Cheryl saying: "The mad thing is, it ended up with Sarah comforting me."
Sarah has been undergoing intensive treatment for breast cancer following her summer 2020 diagnosis, but has now got months left to live after developing a secondary tumour at the base of her spine.
While coronavirus has meant Cheryl and many of Sarah's other friends cannot visit, they have kept in touch electronically.
The two have known each other for the best part of two decades, after they both found fame as contestants on 2002 reality show Popstars.
Cheryl says that Sarah was "the complete blistering blonde package" and adds that her friend was a "wild child."
She writes: "That’s probably the thing I love most about Sarah; she doesn’t have a bad bone in her body."
The two were picked to form Girls Aloud along with three others, and spent the next seven years living in one another's pockets, touring and recording and finding huge success.
Girls Aloud's achievements included 20 consecutive top 10 singles in the UK, with four hitting number one, and platinum studio albums. They won a Brit Award for The Promise, which Sarah calls: "one of the biggest moments of my life."
Sarah also tried her hand at acting, taking a cameo role in 2007 St Trinian's before starring in a low-budget thriller.
Reflecting on her success, Sarah admitted that while fame was "amazing", it wasn't always as "fabulous as it looked."
She explains the band were always incredibly busy and she hated having to ignore fans who had waited to meet her, just to stay on schedule.
She adds: "We all knew we were leading a charmed life compared with most, and I always tried to appreciate that, but I didn't feel glamorous a lot of the time, I can tell you. "
In her book she tells the full story of her diagnosis for the first time, admitting she ignored her growing painful breast lump for months, scared to seek medical treatment during the pandemic.
She also shares how she nearly died after she developed sepsis after a port was put into her chest for chemo.
Doctors have told Sarah that Christmas 2020 was "probably" her last.
However she refuses to dwell on her prognosis, instead making the most of each day she has left.
She spends time with her mum, who is acting as her carer, watches TV and enjoys quiet meals of roast chicken and the occasional lie-in.
Sarah urges fans to seek treatment if they have any suspicion things are not right, saying that was one of the motivations in writing her book.
* Hear Me Out by Sarah Harding is published by Ebury on Thursday.
