With new hookups and breakups, big name guest stars and the culmination of what has been a wild season encompassing many ongoing plot lines, many major game-changing developments are expected with Grey's Anatomy airs its Season Six finale Thursday, May 20.

The words “huge” and “amazing” are being used by the show's brass to describe the upcoming finale while guest stars include Mandy Moore and Ryan Devlin.

Demi Lovato guest stars the previous week. What can we expect next month? Executive producer Krista Vernoff Tweeted: “It will seriously blow your mind."

She adds: "It is Shonda Rhimes at her very best!”

So there you go. Let the countdown begin...

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.