Janet Jackson knew of brother's drug addiction 

Source: ReutersJanet Jackson, sister of deceased pop star Michael Jackson, speaks at the BET Awards '09 in Los Angeles

Janet Jackson has revealed that she knew of her brother Michael Jackson's dependency on prescription drugs and even staged an intervention to tackle the problem.

The pop star said in an interview with ABC's Robin Roberts that the Jackson family got together to confront the late King of Pop about his drug use, but to no avail.

"Those are the things that you do when you love someone. You can't just let them continue on like that," she said. "And we did (attempt interventions) a few times. We weren't very successful. He understood that it was out of love, out of caring. But when it's something like that people can tend to be in denial," she said.

Despite their attempts Michael continued his use of painkillers and the powerful sedative Propofal, which is believed to have killed him.

Jackson was being treated by his personal physician , Dr Conrad Murray when he suffered a cardiac arrest on June 25 and could not be revived at his Los Angeles home.

Jackson was about to embark on his comeback This Is It concerts. Footage from the rehearsals have since been turned into a movie of the same name which hit theaters in October and has become the top grossing musical documentary of all time with more than $US200 million in sales worldwide.

Speaking about her relationship with with her brother, Jackson noted that they were "incredibly" close and that she had seen him one month prior to his death. "We last saw each other two days before my birthday. We had a lot of fun, laughing. He was sitting in front of me cracking up - just laughing."

Since his death, Jackson said she is doing "well" and has continued to focus on her work. The 43-year-old released her 'Number Ones' album this week.