TV Guide reports that Grey's Anatomy and Private Practice will be teaming up for a new, multi-episode crossover story for February sweeps.

The Grey's Anatomy actor(s) involved has yet to be announced, but Kate Walsh's Dr. Addison Montgomery will again visit ol' Seattle Grace.

Addison returned for an episode of Grey's Anatomy last spring after bolting for L.A. and Private Practice after the end of the third season.

What brings Addison (Kate Walsh) back to Grey's Anatomy this time?

What regular(s) from Seattle Grace might show up at Oceanside Wellness Center? Walsh personally is hoping for her former love interest Mark Sloan (Eric Dane), saying, "It'd be fun to have him cause some trouble!"

What star(s) - and story line(s) - would you like to see?

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