Continuing its run as the longest-running medical drama in primetime in the US, Grey’s Anatomy season 21 kicks off another run for the popular series.
It's natural for a show with this much time under its belt to see its fair share of casting shakeups. Over the years fans have had to say painful goodbyes to Sandra Oh's Cristina Yang, Patrick Dempsey's Derek Shepherd, Alex Karev's Justin Chambers and the list goes on. However, in the face of all the departures, the show has also seen some great casting additions, such as Kevin McKidd's Owen Hunt, Camilla Luddington's Jo Wilson and Debbie Allen's Catherine Fox.
