Addison Montgomery

Addison Adrianne Forbes Montgomery, M.D., F.A.C.S., F.A.C.O.G. is a fictional character who appears as a supporting main character on the ABC television series Grey's Anatomy, and as the protagonist of its spin-off Private Practice played by Kate Walsh. Addison is a world-class neonatal surgeon with board certifications in both Obstetrics and Gynaecology and Maternal and Fetal Medicine. Additionally, she has completed a medical genetics fellowship. She works at the Oceanside Wellness Group, a fictional practice located in Santa Monica, California.

Addison joined the series in the first-season finale as Derek Shepherd (Patrick Dempsey)'s estranged wife. Initially set for a recurring guest stint on Grey's, Walsh's character expanded into a series regular position as Rhimes grew fond of Walsh's portrayal of the character. She is promoted to series regular in season two episode seven, "Something To Talk About". She makes her final appearance as a series regular in the season three finale, "Didn't We Almost Have It All?", but returns as a guest star for the following five seasons, including a two-part guest stint in the fifth season.

Once the love-triangle storyline had been resolved, Rhimes created the first spin-off of Grey's Anatomy based on the character named Private Practice which saw Addison move to Los Angeles to start anew, after two seasons as a series regular. The spin-off lasted six seasons, running concurrently with the fourth to ninth seasons of Grey's Anatomy. Walsh deciding to retire the character after eight years of portraying her, making her final series regular appearance in the Grey's Anatomy universe in the Private Practice series finale, "In Which We Say Goodbye" on January 22, 2013. Walsh returned to the role almost nine years later in recurring capacity, for the eighteenth and nineteenth seasons of the original series.