Kim Kardashian West says Rob Kardashian is ''working really hard'' on himself.

The 34-year-old star, whose brother, 28, is reportedly battling depression and has gained more than 100 pounds over the past two years, thinks he's still ''not comfortable in his own skin'' but is slowly getting his life back on track.

The 'Keeping Up with the Kardashians' beauty said: ''I think he's just going through a phase where he's not comfortable in his own skin. And he is working really hard to get back to where he wants to be.''

But Kim doesn't think her family's fame is to blame for Rob's issues and claims he is still struggling to get over the death of their father, Robert Kardashian, from cancer in 2003, and his sister Khloé Kardashian's split from husband Lamar Odom in 2013.

She told the 'TODAY' show: ''I don't necessarily think it's because of the fame. I think it's been circumstances in his life that he just really hasn't dealt with.

''Whether it's, you know, the loss of our father, or certain breakups, or, you know, he was extremely close to Lamar and when, you know, Khloé and him broke up, that was really hard on him. So I think it was a couple things.''

Kim's mother Kris Jenner previously admitted on their E! reality TV series that she was very concerned for Rob's welfare.

She said: ''I feel like if I don't help him do something drastic, that he's gonna die. He's gained over 100 pounds in the last year...He doesn't go out of the house. He's missed Christmas, he missed Kim's wedding.''