Sarah Harding has admitted the party girl pop star wasn't the "real" her.

Sarah Harding

Sarah Harding

The former Girls Aloud singer - who revealed last summer she was battling advanced-stage breast cancer - has opened up about her autobiography 'Hear Me Out', which will be released next month.

She wrote on Instagram: "I can’t rewrite history; all I can do is be honest and wear my heart on my sleeve. It’s really the only way I know. I want to show people the real me. Or perhaps remind them.

"Because, somewhere - amongst the nightclubs, the frocks and hairdos, the big chart hits... and the glamour of being a popstar - the other Sarah Harding got utterly lost.

"She’s the one who’s been forgotten. And all I want is for you to hear her out."

The 39-year-old star told her social media followers she'd try to be more "present" on the platform, while revealing how much their support means on her "bad days".

She added: "I know I’m not really that present on here which I promise I’ll try to get a bit better at, as honestly it means the world to me when I come on and see all your well wishes.

"Thank you for the love and support, on bad days it helps me so much. So here’s a little update from me…

"Mum, the dogs and I had a really lovely but quiet Christmas together, which was different to my usual, but seemed a fitting way to end such a strange year.

"And since then, in between treatments and hospital visits I’ve managed to finish my book! I can’t believe I’ve actually gone and done it and it’s now at the printers! I’m so excited for it to come out."

Sarah has named the book after a Girls Aloud song, which she penned for their 2004 record 'What Will the Neighbours Say?'

She explained: "I called the book ‘Hear Me Out’ because it’s the title of the song I wrote on the second Girls Aloud album and I’ve always really loved it. The lyrics have always meant a lot to me.

"It’s been lovely revisiting our songs, looking back over photos and writing down memories from my last 39 years. I really hope you might enjoy reading about them too."