Watch This And Tell Me She Isn’t Trippin’

TMZ -- The video was shot by Howard K. Stern at a little girl's birthday party. Snippets of the video were released two years ago, but now the entire 50-minute tape is being used in the drug case against Stern and Anna's former doctors.

In this particular clip, Smith can't seem to comprehend the fact that she's pregnant -- consistently denying there's a baby in her belly ... despite the fact she's showing.

Source: http://www.tmz.com/2009/10/31/anna-nicole-mistakes-pregnancy