'Grey's Anatomy,' 'Private Practice' cross over again
``Grey's Anatomy'' and ``Private Practice'' will cross over again in early 2010, with former lovers Addison Montgomery and Mark Sloan popping up on each other's shows, the network confirms.
Kate Walsh, whose Dr. Addison Montgomery is the ``Grey's Anatomy'' character who sparked the ``Grey's'' spin-off ``Private Practice,'' will be leaving ``PP'' next season.