Khloe Kardashian is "obsessed" with her brother Rob.

Khloe Kardashian

Khloe Kardashian

The 31-year-old reality star wishes her younger sibling - who has retreated from the spotlight due to his unhappiness with his weight - could see himself in the way she does in order to boost his confidence.

Alongside an old picture of herself and Rob - who lives with her - she wrote: "If only you could see yourself through my eyes! I'll forever be obsessed with you! My one and only!#MyAce (sic)"

In October, the 'Keeping Up With the Kardashians' star admitted she finds it frustrating watch Rob struggle.

She said: "Rob is such a great guy. He's charming, charismatic, everything. That's what's so infuriating. I'm like, 'Where is your will to live life? Let's be around people!'

"I've been working on my patience. I've been really trying. But I have my moments and I do snap. I've offered to get a chef, I'm like, 'What's your excuse?' But it's not just that. I can't win life for Rob. I have to wait until [he's] ready to do it for himself."

And earlier this year Khloe said her 28-year-old brother was "trying to get his groove back" but had a lot of problems to deal with.

She said: "It's not just one thing. I think it's a ton of things. The loss of my father, he's never really dealt with -- he went straight into college after that happened and kind of pushed everything aside and manifested himself in college and did so well and succeeded in school.

"Also, losing Lamar in his life was a big thing for him because he lost his next father-slash-brother figure."