ABC has just announced that it is renewing its flagship series for a new season. This will be the 21st, making "Grey's Anatomy" the longest-running prime-time medical series in the history of American television.

Season 20 has only just started in the United States, due to the writers' and actors' strike in Hollywood. The first episodes attracted an average of 3.5 million viewers in total across the Atlantic, following in the footsteps of season 19. But be careful, the new season of the medical series could well differ from the last ones broadcast.