AceShowbiz - Whitney Houston and Bobby Brown's teenage daughter has slammed suggestions she's struggling with substance abuse after a U.S. tabloid published photos purportedly showing the teen snorting lines of cocaine.

Bobbi Kristina found herself at the center of a drug scandal on Wednesday, March 2, when the National Enquirer obtained damning shots of a youngster alleged to be the celebrity offspring indulging in cocaine at two different parties. Houston and Brown have both battled substance abuse in the past and the magazine suggested their 18-year-old kid had picked up the troubled stars' bad habits too.

An ex-boyfriend of Bobbi Kristina - known to her friends as Krissi - reportedly supplied the snaps to the Enquirer, telling the magazine, "During the first few months I knew her, I can't remember a time that she stayed sober all day. But it was difficult to stop her from buying alcohol and drugs because her mother gave her $1,000 a week. I saw Krissi do an eight ball - an eighth of an ounce - of cocaine in just two days with friends."

But Bobbi Kristina has taken to Twitter.com to blast the allegations, claiming the former boyfriend went to the tabloid in an act of revenge for "a horrible relationship that went sour". In a series of tweets, she wrote, "A former very dear person to me did this. Set me up to make it look exactly what it looks like... But it's really not what it looks like. People will do anything for money which is extremely sad, and I'm very hurt by this."

She reveals her superstar mother has been comforting her through the controversy and the 18 year old insists she is only taking after her parents career-wise: "I'm following my mother's footsteps industry wise. My family is great - and I know I will overcome this and succeed. This is all I'm gonna say." The tabloid scandal emerged just two days before the youngster's 18th birthday on March 4.