“I’m so excited to be home again,” Walsh said in a video announcing her return.
Walsh joined “Grey’s Anatomy” in the first season, in a memorable finale moment that introduced main character Meredith Grey (Ellen Pompeo) to the wife of her love interest, Derek Shepherd (Patrick Dempsey).
A neonatal surgeon, Addison became a fixture on “Grey’s Anatomy” until leaving to star in a spin-off, “Private Practice.” That show ran for six seasons from 2007-2013.
The new season of “Grey’s Anatomy” premieres September 30 on ABC.