Big Brother Australia 2007, also known as Big Brother 7, was the seventh season of the Australian reality television series Big Brother Australia. Episodes were broadcast on Network Ten in Australia, and the first episode aired on 22 April 2007. Despite a drop in ratings compared to previous series, and a number of controversies, the then Big Brother executive producer Kris Noble considers the year's series a success. At the end of this season's finale broadcast 30 July 2007, it was announced by host Gretel Killeen that Big Brother would be returning for an eighth season in 2008. In the finale Aleisha Cowcher was announced winner of Big Brother Australia 2007. She won by the closest winning margin ever in the Australian series. The news the following day reported a margin of 51% versus 49% - a difference of 65 votes. This was the last season hosted by Gretel Killeen.