The singer seemed a bit miffed that she wasn't included in the 30th birthday party when other Girls Aloud bandmates Cheryl Fernandez-Versini and Kimberley Walsh were both there.
Sarah told The Sun: "I didn't get a f**king invite to Nicola's birthday! But you know what? I am independent so whatever. I nearly tweeted about it but I thought I better not. If I had an invite I would have gone but I didn't.
"Relations were good between us until I didn't get an invite. I can't see a Girls Aloud reunion happening any time soon, let's put it that way."
Nicola marked her 30th on Sunday night at the Hotel Chantelle in Mayfair, London. Pictures posted to Instagram showed her with Cheryl and Kimberley.
A gushing Cheryl said: "Nicola looking BREATHTAKING for her 30th!!!! Aaaarrgghhhhh when did that happen? She was just 17 a minute ago. Not a better feeling in the world than dancing until it hurts with these two beauties. Happy birthday Ginge. I love you more than words."
Girls Aloud formed on the ITV show Popstars: The Rivals back in 2002 and went on to become the UK's biggest-selling girl group of the 21st century, shifting more than four million albums and four million singles in the UK alone!
In 2009, they announced a year-long hiatus but that break ended up lasting until 2012, when they reunited to mark their tenth anniversary, embarking on a reunion tour of the UK and Ireland and releasing a Greatest Hits album, containing new song 'Something New'.
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