Cheryl turned 31 yesterday (30 June) and was later pictured on a private plane celebrating her birthday as she headed to Scotland for the last leg of the X Factor auditions.
Along with Mel and their pals, the Girls Aloud star was joined by her boss and fellow X Factor judge Simon, who incredibly didn't hold back on getting involved!
In a new picture, which Cheryl posted to Instagram, the gang - including Simon - can all be seen wearing metallic pointy party hats. And Simon is even smiling...sort of!
Commenting on the funny snap, Chezza joked: "Birthday selfies on the way to Edinburgh. Yes. That is Simon in a blue party hat #blame @officialmelb."
However, while we're sure they all had a good laugh at Simon's expense, he has already got his own back on the Geordie star.
Taking to Twitter, Simon has since ribbed: "Now what shall I get Cheryl for her birthday? 40 is an important year." OUCH!
Despite their differences in the past, these two love nothing more than to play pranks on each other. Who can remember the giant plane with banner that Cheryl hired when Simon turned 50?!
Meanwhile, Cheryl has been inundated with birthday wishes from her friends and fans. Yesterday, pregnant pal Kimberley Walsh posted a throwback photograph of herself with Cheryl and Girls Aloud taken on her 21st birthday.
More importantly, Cheryl was also treated to a very romantic night at a hotel - surrounded by dozens of roses and candles - believed to be a gift from her new boyfriend Jean-Bernard Fernandez-Versini.
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