Initial papers have been filed with the court to probate Michael Jackson's estate. But it seems Jackson's mom and dad don't know Jackson had a will.

The petition was filed by Michael's parents, Joe and Katherine Jackson. But here's the thing. The papers say Jackson died "intestate" -- that means, without a will.

But we've learned Jackson's long-time lawyer, John Branca, who just came back on board 3 weeks ago, has a will Jackson signed that he intends to file within 30 days.

The petition asks that Katherine be named as administrator of the will ... meaning she wants to call the shots.

The papers say Debbie Rowe will be served with notice of a hearing.