Shallow Hal was a fairly funny Farelly Brothers romantic comedy about a shallow man unable to find a woman to satisfy him who is hypnotized (by Tony Robbins of all people) to only see the inner beauty of people. This leads him to Gwyneth Paltrow, who he sees as a ravishing beauty but the rest of the world views as a very heavy woman.
There's a simple lesson about not judging a book by the cover but some it gets loss underneath the endless fat jokes and related sight gags. The Godfather it isn't, but it's not an awful way of spending a couple of hours if you're looking for a laugh.
The clip below is a scene where Gwyneth (seen by us in her usual slender, sexy form) takes a dive as the bench below her collapses under her character's prodigious weight, leading to a brief glimpse of her thong. I've included both the clip and a slow-motion version in the .zip.
I was going to clip the far more often seen scene where Gwyneth strips out of lingerie to reveal her ass in a thong but, alas, the director's commentary confirms that it was a butt double.