Kourtney Kardashian causes a stir with cryptic Instagram snap

Kourtney Kardashian has been lying low since giving birth to her third child, a son called Reign, shortly before Christmas. The reality star has been keeping fans updated via her Instagram and Twitter accounts – but we're not sure what she was getting at with her latest post!

Kourt confused fans when she posted a seriously old throwback snap of her and younger sister Kim showing off their bodies some sexy beachwear:

In the picture, believed to have been taken around six years ago, the sisters are seen strolling onto a yacht, with Kim pointing in the direction of the camera.

The photo was posted with no explanation and was simply captioned " What? We know…"

We're not sure if Kourtney is longing to get back to her old toned self, hinting at a new show or just reminiscing on some happy memories… but it seems like an odd choice to us for a family throwback picture!

The 35-year-old has not been seen in public since Reign's birth, aside from some sweet snaps she shared of her and Scott on New Year's Eve:

We hope she'll be out and about soon!