A band picture comprising just Walsh, Cheryl Cole, Nicola Roberts and Sarah Harding recently appeared on Twitter, sparking talk that Coyle had quit the group.
Clearing up the rumours, she told Fabulous magazine: "That was taken at my house. We all got together like we do every few months.
"Sadly, Nadine couldn't be with us because she was in the States, but we did miss her.
"There was no mystery about the picture, we just did it on the spur of the moment. We all hid our faces because we were all looking a bit spotty and we'd had a couple of bottles of wine."
Walsh added: "But we were having such a great time being together that we just wanted to share the moment with our fans. We're all talking about the reunion, maybe for next year."
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Watch Girls Aloud's 'Something Kinda Ooh' video below: