Kate Middleton Conspiracy Theorists Say New Video is Not Her!!!

The new Kate Middleton video -- showing her surfacing for the first time since Xmas -- is bogus, and it's NOT her ... so say a bunch of conspiracy theorists who claim to have receipts.

TMZ's video, shot over the weekend, shows what appears to be a healthy and happy Kate strolling out of a food store with hubby Prince William.

They point to Kate's height relative to William. In previous outings, they say Kate is shorter than she appears in the new video. In previous photos, Kate's eye line hits around William's neck, but in the new video, she's closer to his nose.

What's interesting ... in the old photo and new video, Kate is wearing flats, which leads folks online to believe the new video is a fraud.

Now there may be an explanation ... in the old photo, Kate seems a bit hunched over, whereas in the new video she's holding her head up high.

The social media crew also believes her hairline is different as is her chin. They say her chin seems stronger in the old photo. On the other hand, she seems thinner than before, which could account for her thinner facial features.

And, there's something else that leads online sleuths to believe the video was shot during Xmas, not over the weekend. Check out the shed covered in Christmas lights and garland. Thing is, we got a new photo shot Monday, and the lights and garland are still there.

Kate is recovering from abdominal surgery, so says the palace ... but her stride is strong as she carries a shopping bag out of the store.

We looked at the metadata on the new video -- which showed it was taken on Saturday near the royal couple's home in Windsor.

We covered it all on the latest episode of The TMZ Podcast, available on all podcast platforms.