Sarah Harding: Girls Aloud stars Kimberley Walsh, Nadine Coyle and Nicola Roberts lead tributes to singer

Watch: Girls Aloud stars Kimberley Walsh, Nadine Coyle and Nicola Roberts lead tributes to singer

Girls Aloud stars Kimberley Walsh, Nadine Coyle and Nicola Roberts have led the tributes to former bandmate Sarah Harding following her death at the age of 39.

Following social media posts by Coyle and Roberts on Sunday after Harding's death from cancer earlier that morning, Walsh shared an emotional message on Monday, saying her "heart is broken".

"Beautiful Sarah this hurts so bad," Walsh wrote on Instagram, alongside three photos of the pair during their Girls Aloud days. "To wake up and know that you are really gone is too much to bear.

"Hearing your infectious chuckle was one of my favourite things in the world. Your fire burned so bright and you loved, lived and laughed so hard. Sending love and strength to everyone who is grieving today. My heart is broken."

Walsh's post comes after poignant tributes from Coyle and Roberts.

Sharing a picture of Harding laughing on Instagram, Coyle said: "I am absolutely devastated!! I can't think of words that could possibly express how I feel about this girl & what she means to me!! I know so many of you will be feeling this way.

"For now I'm sending so much love to you!!!"

Roberts shared a number of photos of her and Harding together and paid tribute to an "electric girl" who "gave everything" at all times.

"I'm absolutely devastated and I can't accept that this day has come," she wrote. "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.

"Electric girl, you made us. 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."

Watch: Sarah Harding 'fought incredibly hard for fifteen months' and was 'really resilient', says consultant who treated her breast cancer

The news of Harding's death was announced by her mother, Marie, on the star's own Instagram page on Sunday.

She described her daughter as a "bright and shining star" and said she hoped that is how she would be remembered.

The Girls Aloud stars' messages were among the celebrity tributes that poured in, with fans and friends sharing their memories and anecdotes of Harding.

The judges of the show which made her famous, Popstars: The Rivals, also shared their memories.

"She was always fun and the life and soul of the party," Louis Walsh said in a statement. "Anytime she came to Dublin in the early days we went out to the pod nightclub and would be the last to leave.

"It's just so unfair, I was hoping she was getting better. She was fun and loved music, dancing and life. I will remember her with great fondness."

Pete Waterman, a judge on the show that made Girls Aloud, told Sky News it was difficult to get his head around the news of Harding's death.

Saying she was "just so young really", he described her as being "full of life" and an "exceptionally talented person".

"I remember going to her house in Manchester to tell her that she was picked to go into the group," he said.

"I mean, she ran upstairs and was jumping on the bed with joy... She was typical of what it was all about, excitement, you know, just real enthusiasm."

Meanwhile, fellow judge and Spice Girl Geri Horner simply wrote on Twitter: "Rest in peace, Sarah Harding. You'll be remembered for the light and joy you brought to the world. X."

Elsewhere, Davina McCall, who hosted the show, said: "So so sad to hear about Sarah ... a star from the get go, hugely fun and outgoing yet also somehow fragile".

Model Katie Price also shared a tribute, writing on Instagram: "You were always such a genuine and honest person, I will remember the all laughs we used to have back in the day... I always valued Sarah's friendship and my thoughts go out to her family and friends."

Other stars paying tribute also included ITV talent alumni Joe McElderry and Michelle McManus, who both described Harding as "lovely", and Boyzone member Mikey Graham, who wrote that her "high energy was infectious".

Former partner and reality star Calum Best shared a number of pictures of the pair together on Twitter, writing: "Jesus this one hits home, so damn sad, so young.

"I hope u rest In peace Sarah we had some crazy fun times and adventures.

"U will be so very missed. Sending so much love to ur mom."

Other stars paying tribute to the much-loved performer include Spandau Ballet member Martin Kemp, Steps singer Ian "H" Watkins, and TV presenter Vernon Kay.

Watch: Sarah Harding in action with Girls Aloud