The Big Bang Theory is heading to Channel 7. Source: Supplied

Seven confirmed the deal today, taking the popular US sitcom away from rival Nine, which has held the rights to the replays for the past several years.

Seven plans to roll out seasons one to seven, comprising 159 episodes, on its main channel and digital channel 7mate from October. It will take the rights to season eight in 2016.

“The Big Bang Theory provides demographic certainty for Seven. It will ensure we have Australia’s biggest digital channels and will give 7mate unprecedented demographic dominance,” Seven head of programming Angus Ross said.

Nine will retain the rights to new episodes of The Big Bang Theory, including its upcoming ninth season, set to premiere on September 21 in the US.

The CBS comedy has been a massive hit for Nine, which has relied on airing episodes as a gap-filler during non-ratings periods and during prime time slots when local content underperforms.

The network has already aired 150 hours of The Big Bang Theory this year.

The rights for the series have been effectively up for grabs since Nine pulled back on its output deal with Warner Bros studio.