Kensington Palace to Reveal Major Update On Kate Middleton's Health

Kate Middleton's mystery disappearance from public view will be solved shortly, TMZ has learned, because Kensington Palace is about to reveal specific details on her health.

Sources with direct knowledge tell TMZ ... the British media has been briefed on Kate's condition, but there is a strict embargo on the information until 2 PM ET, 11 AM PT.

We're also told the Palace will release a video of Kate speaking on her condition.

Our sources say this statement is dramatic, clear and could well put all the controversy surrounding her disappearance to rest.

As you know, the Palace says Kate entered the hospital in January for "scheduled abdominal surgery," but spent 13 days at The London Clinic before returning home, where she has been recuperating.

TMZ aired a special Thursday night on FOX, in which Dr. George Crawford said 13 days suggests when doctors went in for the surgery, they may have found something else.

We're told the Palace will get specific shortly.

Remember ... this all follows several weeks of speculation and innuendo over Kate's whereabouts and her overall condition -- which has been kept under wraps until now.

TMZ broke the story ... video surfaced showing Kate out and about with William last weekend, and she seemed to be doing well. It was the first real sighing of Kate out in the wild, and on her own two feet, since she had her surgery back in January.

There've been other glimpses of her in cars -- but the Windsor Farm Shop seemed to be the first instance of her walking around. Like we said ... she was happy, and looked relatively OK.

Of course, this whole saga kicked into overdrive nearly two weeks ago when Kate posted a Mother's Day photo that featured her and her kids -- but which was later revealed to be inauthentic. All the conspiracy theories about Kate up to that point only doubled.

Now, it appears Kensington Palace is geared up to set the record straight, right from the Princess's mouth.