Los Angeles, Jun 18 (IANS): Singer Whitney Houston hid her drug habit from her friends, says a close friend.

"It really shocked me when I found that out. And actually it made me quite mad because I thought, 'Whitney, you had us all fooled.' Everyone thought Whitney was in a good place and we never imagined anything like this was going to happen," Houston's friend and entertainment consultant Raffles van Exel said.

Exel also believed that she had quit drugs two years back, reports contactmusic.com.

"I honestly thought she was clean in the two years before she died. Yes, she would have the occasional drink. And I knew she was taking painkillers and the anxiety drug Xanax. But I never suspected she was using hard drugs," Exel said.

In February this year, she was found dead in the bath tub of her hotel room. She was 48. According to reports, reason detected behind the sudden death was a massive heart attack, which partially happened because of cocaine consumption.