Kim Kardashian shows off unbelievable hourglass shape... while Kourtney's baby bump disappears

PUBLISHED: 17:37 EST, 28 March 2012 | UPDATED: 00:41 EST, 29 March 2012

Her curves are the fascination of fans across the world so what better way to show off their latest line of swimwear than by using Kim Kardashian to model.

The reality star, 31, showed off her hourglass shape in a bikini from her Kardashian Kollection - the fashion line she shares with sisters Khloe and Kourtney.

But there's something about the shoot and the girls' appearance that just seem impossible - most notably the difference between Kim's middle and her hips.

Incredible Kurves! Kim Kadashian shows off her hourglass shape as she models the family line of swimwear

Kim's waist appears unbelievably tiny and the frilly duke-blue bikini certainly complements her shape which looks incredible.

The reality star is joined by her sisters Kourtney and Khloe in the picture which boasts a brooding theme with dark dramatic clouds seen in the background.

Kourtney,32, is seen sporting a dark strapless bikini while Khloe wears a lace bikini with a sheer navy kaftan over the top.

Nipped in: Kim's looks a lot smaller in the photo for the new Kardashian Kollection, compared with her appearance at her brother's birthday party earlier this month

Kim

Nipped in: Kim's looks a lot smaller in the photo for the new Kardashian Kollection, compared with her appearance at her brother's birthday party earlier this month

The girls skin appears luminous and flawless suggesting the trio have undoubtedly had a little help in the photoshop department.

In fact Kourtney, who is currently pregnant with her second child, was seen sporting a baby bump at the time of the shoot in February, but there is no hint of a pregnancy in the snap.

Her abs looked more toned than ever despite photographers capturing her baby bump in snaps on the same day last month.

Oh baby! At the shoot in February Kourtney Kardashian was already sporting a little baby bump, but in the photo she appears to have a totally flat stomach

Where's the baby? The 32-year-old's stomach appears incredible toned in the picture despite the fact she was showing off a bump at the time of the shoot

Kim took to Twitter today to promote the shoot and posted the snap with the caption: 'Kourt, Khloe and I put on our favorite bikinis for our new #KardashianKollection swimwear shoot!

The picture, which seems to have considerable photoshop work on it, comes a day after Kim was seen leaving a skin and hair clinic in LA with red patches on her forehead.

It seems the star may well have indulged in a spot of Botox ahead of a glitzy event last night.