Kim Kardashian's kitten Mercy has died.

The 'Keeping Up With The Kardashians' star received the white Persian cat from her boyfriend Kanye West in September but after discovering she was allergic, she gave him to her sister Khloe's assistant Sydney Hitchcock, who had recently lost her own cat.

However, after Mercy became ill in November, she was rushed to a vet where she was diagnosed with a fatal cancer like virus which attacked her stomach and both Kim and Sydney are devastated.

A source told E! News: ''Kim is really upset. She was upset about Mercy dying and upset that she was trying to do something nice for Sydney and then she fell into a situation where [Sydney] had to grieve another kitty. Kim called the breeder and said they should be more responsible.''

Kim previously revealed she was worried people would start to think of her as a ''cat lady'' because she couldn't stop posting pictures of herself and Mercy on Twitter.

She said: ''I just hope I'm not turning into one of those cat ladies that's tweeting too many pictures of her pet!

''I have always wanted a white Persian cat with light eyes. That was my thing. I've been always looking at kittens like that online.

''My mother actually helped me come up with that name. It's a song of my boyfriend's, so I thought it was cute. I just thought it was a cute name and it fit her.''