Michael Jackson's mother Katherine is currently in the midst of a wrongful death suit against tour promoter AEG Live, which she claims was responsible for the death of her son because the company hired embattled doctor Conrad Murray to look after him. But now she has something new to worry about.

Seems Debbie Rowe, Michael's ex-wife and the mother of his children Prince and Paris, is set to testify -- but lawyers are concerned she might say under oath that Michael is not the kids' biological father.

To the surprise of absolutely no one, of course.

AEG has already taken care of Rowe's deposition, according to TMZ, but none of the questions had to do with the true paternity of MJ's children. But if AEG chooses to go that route in court, it could ruin Katherine's claims for damages for the kids since they wouldn't legally be Michael's.

In response, Mrs. Jackson's lawyers have filed paperwork requesting paternity be left out of the case, but the judge has yet to rule on that. Which may not matter anyway, since under California law, if a man lives with a woman at the time of conception, he's considered to be the resulting child's father (unless he's impotent or sterile).

In addition to Debbie Rowe, Prince (the purple pocket-sized musical genius, not Jackson's son) is also one of hundreds of witnesses who are supposedly testifying. Why? Well, no one's quite sure yet, but we're guessing it has something to do with lawyers getting paid by the hour.