Rob Kardashian is ''doing very well'' with his weight loss.

The sock designer - who has retreated from the public eye over the last few years because of his unhappiness with his size - is working hard to get back in shape and is really ''taking care of himself''.

Speaking after a slimmer Rob returned to Instagram earlier this week, his friend Malika Haqq said: ''Rob is doing very well. He has been working out and taking care of himself. I think Rob shares what he wants to share. I think that's how it should be for everyone. When you're ready you post, post. When you're ready to be seen, be seen. When you don't, leave him alone.''

Malika and her sister Khadijah Haqq McCray are very protective of the 'Keeping Up With the Kardashians' star.

Khadijah added to E! News: ''We're really defensive about Rob. He's like a little brother.''

It was recently claimed 28-year-old Rob has hired a private chef to help with his weight loss.

A source said: ''For the first time in a long time Rob is committed to changing his diet habits. He's been working with a chef and doing really well.''

Rob has also stepped up his exercise regime with his personal trainer Gunnar Peterson, with the source explaining: ''His regimen involves more than just cardio and weights.''