Big Brother Australia 2005, also known as Big Brother 5, was the fifth season of the Australian reality television series Big Brother, and was aired on Network Ten in Australia, and TV-2 in New Zealand with a four-week delay. The series started on 8 May 2005, with housemates going into the House the day before, and finished on 15 August 2005, lasting 101 days. The theme for this season was "single, sexy, and competitive". Auditions for housemates were held in March 2005. In a departure from usual procedure, candidates were not required to send in videos of themselves as had been the case for prior auditions. Instead, the producers toured major Australian cities and conducted interviews. They searched for sexy singles that were willing to have sexual relations on camera. Promos for the show suggested that Big Brother would be different this year, and phrases such as "Assume Nothing, Expect Anything", "Let's Play", and "Think Again" were used throughout the series, especially during Opening Night. The winner announced on the finale that was watched by 2. 282 million Australian viewers.