Khloé Kardashian believes her brother Rob is suffering from ''social anxiety.''

The 'Keeping Up With the Kardashians' star, 30, has admitted her younger sibling, 28 - who reportedly asked to be pulled from their family reality TV show last year after piling on the pounds and falling out with his sister Kim Kardashian West over her wedding to Kanye West - isn't in his ''happiest place'' at the moment.

Khloé said: ''I just feel, especially over the last year, Rob has become very introverted and has a kind of social anxiety.''

However, the blonde beauty is hopeful the sock designer can change his negative thinking and get back to the person he once was with a little support from his family.

Speaking to WonderWall, she explained: ''He's definitely not at his happiest place that he once was and I know he can get to that happy place and he will.''

She added: ''We all kind of get to a place where you don't know where to go in life or whatever, so I think it's important for him to know that he always has people to lean on and it's not unnatural for people to not know where to begin. It's a growing process. I will always be his number one supporter.''