SAM & BILLIE:

hey proudly flaunted T their incredible post-baby bodies in bikinis on a family trip to Ibiza last week, and sisters Sam and Billie Faiers are thrilled with the results of their recent shape-ups.

Pals close to the size 8 TOWIE stars say they’ve been motivating each other since Sam, 25 – who went up to a size 10-12 during her pregnancy – gave birth to her son Paul with boyfriend Paul Knightley in December, with a joint workout and diet plan.

Billie, 26, who’s engaged to businessman Greg Shepherd, shed a stone after giving birth to daughter Nelly, now 22 months, in July 2014. She went back down to a size 8 thanks to a sensible diet and lots of walking.

A source says: “Sam and Billie formed their own ‘diet club’ after Sam had Paul and they decided to help each other shape up.

“Sam wanted to lose 2st of baby weight and Billie was keen to tone up and lose a few pounds so they embarked on a fitness journey together. They’d do fitness DVDS and Sam would devise workouts for them to do while Nelly and Paul were napping.

“If nap timings didn’t work, one would look after the kids while the other one worked out, and they’d ensure they would exercise at least five times a week.

“They even Facetime each other in the morning and get in a quick 10-minute blast of squats and abs work before the babies wake up!”

Sam, who is 5ft 5, overhauled her diet when she was diagnosed with Crohn’s disease last year and pals say Billie, who’s 5ft 3, has adopted her strict meal plan.

A source adds: “The girls have cut out processed foods, sugar and complex carbs together.

“They don’t let the boys bring any junk food into the house and doing it together and having that support has helped keep them on track.”