Tina faces an identity crisis on next week's Glee episode, while Rachel confronts her birth mother.

But the major, exciting news for all fans of this show is Will's assignment to the singing group: make like Lady Gaga.

The official promo for "Theatricality" gave us a look at the installment, while we've got more for you below:

• Episode stills from the upcoming hour;
• A "Poker Face" duet by Rachel and Shelby.

ENJOY!

[video url="http://www.tvfanatic.com/videos/poker-face-audio/" title="Poker Face Audio"] [/video]

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