Janet Jackson caused a stir in a Los Angeles court on Tuesday (28May13) when she joined her mother Katherine and sister Rebbie as the family's ongoing wrongful death trial began its fifth week.

AEG Live attorneys protested to Judge Yvette Palazuelos, reminding her she had previously ruled that Katherine could only be joined by one family member, as many of the Jacksons are on the witness list. Palazuelos offered to revisit the issue later in the day.

Meanwhile, taking the stand on Tuesday, an executive at AEG Live has confessed he knew of Jackson's issues with painkillers when the King of Pop signed on for his ill-fated London comeback concerts.

Paul Gongaware testified that although he knew of the pop superstar's dependence on medication, he had no idea he was abusing prescription drugs until the Thriller hitmaker cancelled his Dangerous world tour in the early 1990s to enter rehab.

Gongaware, who was the manager of the Dangerous tour, revealed he knew a doctor was medicating Jackson at the time.

Katherine Jackson and her late son's three children have accused the concert promotion company of negligently hiring and controlling Dr. Conrad Murray, the medic who was jailed in 2011 for involuntary manslaughter after he was found guilty of administering a fatal dose of the surgical anaesthetic Propofol, which claimed the life of Michael Jackson in 2009.

The Jacksons also claim AEG Live bosses ignored the King of Pop's ongoing medical problems as his This Is It concert run loomed.

The case continues.