One wore a black T-shirt that read: "We support you Katherine."
Fans regularly attended the months-long trial, watching from an overflow room or one of the coveted public seats raffled off each morning. A short cheer broke out Friday for the woman who received a ticket allowing her inside the courtroom.
"Yay!" one of the other fans said. "I had a feeling."
Katherine Jackson and her the singer's three children -- Prince, Paris and Blanket -- filed a wrongful-death lawsuit against AEG Live, the company that was promoting the singer's ill-fated comeback tour. It would be her first court appearance in the case.
The suit claims the entertainment giant negligently hired and controlled the physician who gave the singer a fatal dose of the anesthetic propofol in 2009, days before his "This Is It" tour was to open in London.
AEG says it was Michael Jackson who hired Dr. Conrad Murray, and that any money the company was supposed to pay the doctor was an advance to the singer.
Murray is serving jail time for his involuntary manslaughter conviction.
Other Jackson family members have already testified in the trial, which began more than two months ago and could continue through October.
Michael Jackson's eldest son, Prince, took the stand in late June, when the 16-year-old testified about his childhood, his father's preparations for the "This Is It" tour, and the day the singer died.
Two of Michael Jackson's nephews have also testified, including TJ Jackson, who with his grandmother shares guardianship over the King of Pop's children.
Katherine Jackson has spent much of the trial seated in the front row of the courtroom, where she has been well-received by her son's fans who also routinely watch the proceedings.