For the first time in the show's history, many cast changes occur, seeing the first departure of two main cast members. The season received mixed response from critics and fans, resulting in several awards and nominations for the cast members and the production team. Show creator Shonda Rhimes heavily contributed to the production of the season, writing five out of the seventeen episodes. The highest-rated episode was the season premiere, which was watched by 20.93 million viewers. The season was interrupted by the 2007–2008 Writers Guild of America strike, which resulted in the production of only seventeen episodes, instead of twenty-three originally planned.