Kim Kardashian West was left shocked when her daughter asked why she's famous.

The 37-year-old reality star - who has North, five, Saint, two, and seven-month-old Chicago with husband Kanye West - wasn't prepared for the questioning from her oldest child, but she was able to quickly satisfy the youngster's curiousity and helped the little girl come to a realisation about her own life.

She recalled North had asked: ''Mom, why are you famous?''

She then added to Big Boy on Real 92.3: ''Oh, OK, OK. I'm going to have to explain this right now.

''I'm like, 'We have a TV show.' And she was like, 'Oh OK.' That was the first time she was like, 'Oh!' ''

Kim - who rose to prominence after a sex tape featuring herself and former boyfriend Ray J was leaked in 2007 - was then asked about her daughter's own wealth, as she's been a regular on 'Keeping Up With the Kardashians' since she was born and recently starred alongside her mom and grandmother Kris Jenner in a Fendi campaign.

Big Boy asked: ''Do you think North has more money than us? Like her own?''

Kim laughed and replied: ''North is good.''

Kim recently admitted she doesn't feel very famous because her kids have no idea about her life in the public eye.

She said: ''At home I'm not known. My kids have no clue what's going on. So I don't really feel it -- I spend most of my time at home.''

While North doesn't know much about film, her eight-year-old cousin Mason Disick - the oldest of Kourtney Kardashian and Scott Disick's three children - is very much aware of the family's life on camera.

Kourtney previously said: ''He knows. He doesn't watch it, but I've heard him talk to his friends and say, 'I'm on a TV show called 'Keeping Up with the Kardashians'. I'm like, how does he know that?!'

''Mason calls [the crew] the filmers. He used to be like, 'Are the filmers coming? I want to show them my Legos that I'm building.' Now he's in a phase where he's like, 'I don't like when the filmers are over.' ''