The gals dined at Nozomi restaurant before boogying the night away at Aura.
Rochelle had her bandmates by her side to see in her new age, apart from Una Healy of course who is busy being a new mum to baby Aoife.
[Related article: Una Healy tweets after giving birth, The Saturdays visit Aoife]
Mollie King wore a hot red knee-length number, while Frankie Sandford went for monochrome stripes and Vanessa White donned a multi-coloured patterned frock.
Even a parking ticket couldn't dampen the party mood!
Rochelle's fiancé Marvin was busy with JLS so had to miss out on the fun, but he sent the birthday girl a tweet to let her know he was thinking about her.
Marvin used the JLS account to wish his "amazing fiancée" a happy birthday, adding that he was gutted he wasn't there and that he hoped she had a great night. N'awww.
The birthday girl replied: "I danced hard you'd be proud."
Rochelle, whose birthday is actually today, tweeted this morning about her "stingy eyes and sore head" and admitted she hoped her hangover wouldn't last all day, adding: "This is why I don't really drink!"
Have a great birthday Rochelle!