Grey's Anatomy

Next Thursday, Grey's Anatomy turns 100 episodes young with a blockbuster wedding event. But will the long-awaited union of Meredith and Derek go off without a hitch?

Here's a preview of the episode, entitled "What a Difference a Day Makes." Despite her undying love for McDreamy, Mer is a little nervous about walking down the aisle ...

Elsewhere, Izzie's condition is bad, and getting worse. She's even experiencing familiar symptoms. Handsome symptoms, if you know what we mean. Know what we mean?

If not, click here for more preview clips ...