Kimberley Stewart is suffering from serious liver disease, caused by heavy drinking.Kimberly - the daughter of legendary singer Rod Stewart - is a regular on the London and Los Angeles party scene but, according to her father, her wild lifestyle has taken its toll on her health. Rod said: "She just discovered that she has a very serious liver illness from drinking too much."The 61-year-old star has also revealed that Kimberley has blamed her Scottish heritage for her lifestyle. Rod, who is a proud Scotsman, explained: "She said to me, 'Dad, I'm half Scottish, I thought I was allowed to drink a lot.' I said, 'No, darling, it doesn't work like that.'"The 27-year-old model has not touched a drop of alcohol since being informed of her illness. Kimberly's health problem is the latest blow to Rod, who has been dealing with his son Sean's alcohol and drug addictions.The 26-year-old has been battling his demons since he was a teenager and has had several brushes with the law.