Anamorphic lens effect

If you have seen a J.J. Abrams movies you should know the effect I'm talking about. (He uses them WAY too often.) In case you don't, an anamorphic lens flare (as I understand it) is the horizontal flair effect that is often used in movies or games when looking at a very bright light.

I have seen this effect in MANY videos of Unity games. Its even in the official Unity tutorial video on lighting. (though they don't talk about it.) And in trying not to be a total n00b, I have spent the last few hours googling around trying to find out how its done. Thus far, I haven't been able to figure it out.

TL;DR: How do you get the anamorphic lens effect on bright light sources in unity?