This is how far Glee has come:

A few months ago, the show had yet to even air on Fox. Now, it's gotten so huge that the cast is releasing singles that won't even be featured on episodes.

The latest case in point: a cover of the classic holiday song, "Last Christmas." Listen to it below and then head over to our Glee music section to purchase it off iTunes:

[video url="http://www.tvfanatic.com/videos/last-christmas/" title="Last Christmas"] [/video]

Meanwhile, we've posted an actual clip from this week's mid-season finale. Watch various characters discuss Quinn's baby daddy - and, most urgently, how to keep the news from Rachel - in this scene from "Sectionals."

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.