Girls Aloud reunited for Nicola Roberts 30th birthday on Sunday (04.10.15).

Former bandmates Kimberley Walsh and Cheryl Fernandez-Versini joined the birthday girl in London to celebrate reaching the milestone in style and had a special cake made with Nicola's face iced onto a mermaid's body.

After sharing a picture of the cake on Instagram, Kimberley wrote a message wishing her a happy birthday and thanking the entertainment for putting on a lavish do.

She wrote: ''Amazing 30th birthday party for the one and only Miss @NicolaRoberts thanks to @LoveEnt you're the best! #party #big30 #Nicola's30th... #Happy30thNicola thank you cakegenie (sic)''

The 33-year-old singer then posted a picture of Nicola and herself having a massive hug.

Alongside the photo, she posted: ''#birthdaygirl (sic)''

Kimberley was joined by her fiance Justin Scott - with whom she has son Bobby - while Cheryl attended the bash without her French restaurateur husband Jean-Bernard Fernandez-Versini.

The only members of the girl group not to make an appearance were Sarah Harding, who was also absent when her former bandmates got together at the Pride of Britain Awards last week, and Nadine Coyle.