Big Brother 9, also known as Big Brother: 'Til Death Do You Part, was the ninth season of the American reality television series Big Brother. It is based upon the Netherlands series of the same name, which gained notoriety in 1999 and 2000. Big Brother 9 is the first and only season of the series to air in the Winter time period, due to a writer's strike. The series premiered on CBS on February 12, 2008 and lasted eleven weeks until the live finale on April 27, 2008. The ninth season saw a decrease in ratings when compared to past editions of the series. The season premiered to a total of 7.33 million viewers, the lowest premiere numbers for any season at the time. The season finale had a total of 6.55 million viewers, making it the lowest rated finale at the time. In total, the series averaged 6.56 million viewers, making it the lowest rated season of the series to date. Big Brother 9 featured a total of 16 HouseGuests, the largest amount for any season at the time.