Wanting to share the birthday love, Ferne treated us all to a little present by posting this gem of a photo on Twitter...
They look completely different, right?!?!
Back before their TOWIE days, Ferne and Billie are pictured on a night out... and it's safe to say they are a far cry from their usually glamorous selves.
Proving they too succumbed to poker straight hair, side fringes and a tad too much bronzer, the girls remind us exactly of ourselves all those years ago.
While Billie is seen with long peroxide locks and bead necklaces wrapped around her neck, Ferne is rocking a much darker 'do and plenty of shiny gloss on her lips.
Not quite the same as their Hollywood red pouts and bouncy blowdrys nowadays, ey!
Clearly amused by her old snap, Ferne tweeted alongside her photo: "HappyBirthday @BillieFaiers had to post this. I went through a stage of wearing kaftans to clubs! #13yearsoffriendship."
Although she did make sure to share a collage of gorgeous selfies of the pair too, just in case Billie wasn't so keen on the first!
Meanwhile, Billie also took to Instagram to give fans a glimpse at how she is kicking off her birthday celebrations.
Sharing a sweet picture of her daughter Nelly clutching a pink envelope addressed to 'Mummy', the reality star said: "Happy birthday mummy !!!... The best present anyone could ever ask for ... My beautiful little Nelly."
She also tweeted: "In bed with tea and biscuits with my beautiful nelly noo and @Gregshepherd_ opening all my cards and presents ...Perfect birthday morning." Aww!
In July, Billie gave birth to Nelly - her first child with fiancé Greg Shepherd - and has taken motherhood in her stride ever since.
Last week, Billie marked her daughter's six-month milestone, telling fans: "Cannot believe my beautiful Nelly is exactly 6 months old today ... I love her more then anything in the world and becoming a mummy to her has been the best experience of my life."
The star first announced she was starting a family with Greg over a year ago. Shortly after, Billie then revealed her engagement as her boyfriend had popped the question during a holiday to the Maldives.
They are set to wed this year, although Billie did admit to Reveal she and Greg are still yet to find a venue and a date.
Reveal is now on Google Plus! Join us here for the latest pictures, fashion and celebrity news!