Big Brother 12 was the twelfth 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. The series premiered on CBS on July 8, 2010 and lasted ten weeks until the live finale on September 15, 2010. The twelfth season saw a slight increase in ratings when compared to the past season of the series. The season premiered to a total of 7.35 million viewers, a slight increase from the previous season's launch and the highest for a premiere episode since Big Brother 8. The season finale had a total of 7.89 million viewers, continuing to average slightly above the past season and the highest since the eight edition. In total, the series averaged 7.76 million viewers, higher than that of the previous two seasons and the highest since Big Brother 5 in 2004. Big Brother 12 was initially set to feature a total of 14 HouseGuests, though one HouseGuest left the show before entering the house and was not replaced.