The three friends got together on Thursday (30.11.17) to mark the day the 'Sound of the Underground' hitmaker's first formed on ITV talent show 'Pop Stars: The Rivals' in 2002 and to reflect on their successful career in the music industry, which saw them release five albums before they embarked on their hiatus in 2009, although they reunited in 2012 for a 10-year anniversary tour before going their separate ways again one year later.
And Cheryl, 34, has hailed her time in the group as the ''best, craziest years of [her] life'', and she is honoured she met Kimberley and Nicola, who she has praised as ''two amazing, inspiring gorgeous souls'' and her ''best friends''.
The 'Fight For This Love' hitmaker - who has eight-month-old son Bear with her partner Liam Payne - shared a photograph of her with Nicola, 32, and Kimberley, 36, - who has sons bobby and Cole with her husband Justin Scott - on her Instagram account.
She captioned the post: ''Sitting here drinking coffee with these two and watching babies 15 years later !!! Crazy how time flies... ?
''15 years ago today some of the best, craziest years of my life were just beginning. I had no idea what a life journey I was starting out on. We had some of the most amazing times of our lives and made some incredible pop moments to put the cherry on top.. In the end I left with these two amazing, inspiring gorgeous souls and the best friends anyone could ever ask for. (sic)''
Nicola also shared the same image of the trio, and she has described the moment the group was formed as a life changing moment.
She wrote: ''Girls day with these two today. It is crazy to think that 15 years ago today we were getting ready for our last live show on TV before the public decided who they wanted to make up GIRLS ALOUD. All of our lives completely changed forever. No going back. I'm confident in saying that those early years of the band will always truly be the wildest ride of my life both personally and as a group and no one other than the 5 of us knows how it felt. Happy 15 years Girls Aloud, @cherylofficial , @kimberleywalshofficial , @nadinecoyle , @sarahnicoleharding , our team & the Alouders. (sic).''
The 'Beat of My Drum' vocalist also shared a string of videos of her and her fellow band mates on stage performing on her photo-sharing site.
Meanwhile, Kimberley simply declared her love to the troop.
She wrote: ''Love you all @lilcola @kimberleywalshofficial @nadinecoyle @sarahnicoleharding (sic)''
Nadine, 32, uploaded a clip of the 'Love Machine' music video, which she captioned: ''13 years ago we released 'What Will The Neighbours Say' ? Can't believe how time flies!! (sic).''
While 36-year-old Sarah reflected on her time in the group in October, and shared a video of her riffling through Girls Aloud memorabilia and outfits she wore.
She wrote: ''Who can remember which outfits I wore and when?! #pop #quiz #memories #GA #me (sic).''
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