Kimberley, Sarah, Cheryl Cole, Nicola Roberts and Nadine Coyle all hit London's St Martin's Lane Light Bar together, and posted pictures on Twitter of all five of them giggling and enjoying themselves.
Cheryl tweeted Sarah: "Let's Paaarrrttttyyyyy! Happy Birthday Hardcore... Love you."
Pictures Nicola posted on Instagram showed Cheryl and Nadine embracing and laughing together shattering all rumours of a rift within the group.
Kimberley tweeted the next day: "Go girls g-g-go go go... such a lovely night with my girls last night!"
And Sarah told the band: "thanks for making last night so much fun!!! x x x"
The band - who are celebrating their 10th year together - reunited after several years pursuing solo projects to perform on Children In Need and Strictly Come Dancing at the weekend.