My first thoughts were that it must surely be a speck of something floating about too, then I zoomed in and saw how symmetrical and regular the shape was. Here's another couple of images of just the 'Orb' (or whatever it is).
First one is full size straight from the original pic, the second is zoomed in a fair bit.
Like I said, nothing's been faked, I just want to know what it really is i captured here. I'm doubting it's dust or whatever on the lens - surely it would have been in some of my other shots and it quite clearly isn't.
For more reference, it was a sunny clear evening (around 9.30pm) and it was quite still; the camera was a Fujifilm Finepix S3500, and nothing like this has appeared on any images I've taken before.