Billie's TOWIE co-star Harry Derbidge shared the photo with fans on Twitter and it was taken during series one of the ITV reality show.
Although Billie did not become a main character until later, she did have a small part in the show back in 2010. We just didn't recognise her!
In the snap, the pair are posing at an Asian-themed party and Harry is sporting a fair bit of make-up!
Commenting alongside it, he said: "Me and @BillieFaiers filming series 1 TOWIE, cant believe how different Bill looks, love you Billie #Throwback."
Fans were quick to reply to his post, with one comparing Billie to Harry's cousins and former TOWIE star Amy Childs. Another added: "No way, it's not Billie???"
Things have definitely moved on in Billie's life since she's been starring in front of the cameras. Not only has she opened clothing store Minnies Boutique with sister Sam, the star has got engaged and welcomed her first baby - daughter Nelly - in July!
Did you recognise Billie in this photo? Tell us below, as the best comment from across the website each week wins £50.