This week brings Addison (Kate Walsh) back to Grey's Anatomy in the much-anticipated crossover event with Private Practice. Promotional photos from Thursday's episode show Addison in church, clearly praying for the life of her ailing brother Archer (Grant Show).

But what is Callie Torres (Sara Ramirez) confessing to Addison? And what's up with the rumors of Addison and Derek kissing upon her return to Seattle?

Follow the link for the scoop on these Grey's Anatomy spoilers ...

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