Please help me identify a piece of music

[Tusalu]

So, I watched Bill Bailey´s Remarkable Guide to the Orchestra, and at one point they perform "Tribute to Jellyfish", which is written by Bill Bailey and Anne Dudley. But I'm sure it sounds just like a theme from a movie or game I've seen. Can someone help me identify it? You can hear the music here: http://www.youtube.com/watch?v=MdO3u6ORlGM&feature=player_embedded at 18:08
I think it's from a fantasy movie, and I vaguely seem to remember a voice-over accompanying the music. This has been bugging me ever since I heard it.

[Serpentine]

My Boy reckons it's from Harry Potter. We can't identify a particular part or theme, though.

[Weezer]

It does sound similar to something from Harry Potter, but remember John Williams has stolen a surprising amount of his music from earlier composers, so it may be something completely different.

[Kindablue]

It sounds like the The Planets by Gustav Holst to me, specifically the Neptune Suite (http://www.youtube.com/watch?v=6N6Chjyuf7o&feature=related). When they make soundtracks, the director (or maybe the producer) will put existing music into the film to show the composer how they want the music to interact with the movie, and then they expect the composer to make something similar, which is why so much of Williams's stuff can be traced back to older pieces.

[djqazi]

What Kindablue says about soundtracks is true. I have "the planets" by gustav on vinyl, and after listening to it just now I can say bailey and dudley certainly emulated it. There was very similar transitions and melodies throughout. I would say that "the jellyfish" had a more suspenseful and awesome vibration, possibly because of that badass theremin bill was playing.

good ears kindablue

[Brother Oni]

Thread necromancy.

[Kindablue]

Thread necromancy.

But it's thread necromancy about me! =D