Here's how fox describes the "Extraordinary Merry Christmas" episode: "When New Directions is asked to perform at two different events - on the same day, at the same time - they have a tough decision to make. Will they choose correctly and spread Christmas cheer, or will their ambition get the best of them?"

In the upcoming episode, the cast will cover Band Aid's 1984 hit "Do They Know It's Christmas?" Here, the "Glee" cast members, as well as members of Band Aid (Bono and Sting), talk about creating the "Glee" cover. Proceeds from the "Glee" version of "Do They Know It's Christmas?" will benefit The Band Aid Trust.

"Do They Know It's Christmas?" can also be found on "Glee: The Music, The Christmas Album Volume 2," which features songs from the episode and two originals: "Extraordinary Merry Christmas" and "Christmas Eve With You."

"Glee" airs Tuesday nights on Fox at 8 PM ET.

To watch the behind-the-scenes action on "Glee," look below:

To watch the "Do They Know It's Christmas?" performance, look below: