Former X Factor finalist Katie Waissel has branded Cheryl Fernandez-Versini "fake" and a "pr**k".  Katie was mentored by the X Factor judge when she appeared on the hit ITV show back in 2010. Katie reached the final of the X Factor in 2010.  Speaking to Star Magazine this week, the 29-year-old responded to speculation that she has some bad blood with the I Don't Care singer. She said: "People think that I have this huge grudge against Cheryl. And granted, I do. I'm p***ed off for various reasons. If you ask me, she is fake as sh*t." Katie and Cheryl have had a turbulent relationship.  Referring to Cheryl's return to the judging panel, Katie quipped: "I think she's just there for the money." When asked to explain why she has such a problem with Cheryl, Katie explained: "I just think there's no substance to her. "She can be very abrupt and rude. I don't think she's a very nice human." Cheryl has responded to weight criticism recently.  She added: "My advice to anyone who's going to be on the show would be to f**king beg to get someone else as mentor." The former contestant apparently also offered some advice to new judge Rita Ora. Rita sits alongside Cheryl, Simon Cowell and Nick Grimshaw on the judging panel.  She said: "I told her I hung out with Simon and Louis Walsh, and Cheryl sat with her Benson and Hedges in her dressing room staring at her diamonds. "Rita, if you ever lose Cheryl, that's where she is!" Ouch, Kat's got claws.