Thanks again everyone!
Dani: It is because of my camera. I used a Fujifilm E550 for this shot. Whenever the subject is bright, as are the lights in this photo, the stary effect will appear. I am not sure if this only happens to my camera, or if this is a lens property common in Fujifilm's camera. But I do know that my friends' cameras don't do that, and that a special starlight filter is needed in SLR's. So I would assume it is a defect from the camera.
The effect is genuine, ie. it is as shot from the camera, not added.