The telecoms giant has today (September 12) announced the "biggest deal in the history of UK club rugby", after signing a contract worth £152 million for the TV rights.
Live Premiership Rugby matches are currently split between Sky and ESPN, but the coverage will go exclusively to BT from the 2013/14 season onwards.
BT also recently poached Premier League rights from ESPN in a massive £700m+ deal, giving it access to 38 games per season from 2013/14.
The company intends to launch its own sports channel to carry the games and distribute this to other TV platforms, although it has not yet given any firm details on this.
Alongside football, BT can now also offer up to 69 live Premiership Rugby matches per season over the four-year period, along with the entire JP Morgan Asset Management Sevens competition.
"This is a game-changing agreement and will deliver a service that I know our club supporters will enjoy," said Mark McCafferty, the chief executive of Premiership Rugby, the umbrella organisation of the Premiership Rugby clubs.
"We are delighted to have concluded our discussions with such an ambitious partner that will help bring Premiership Rugby to new audiences.
"BT is a company at the cutting edge of technology and that is one of the reasons it makes them such an exciting broadcast partner for Premiership Rugby."
BT is banking on a big spike of interest around rugby, as the period covered by the deal will see the Rugby World Cup finals staged in England in 2015 and Rugby Sevens played at the 2016 Olympic Games in Rio.
Marc Watson, the boss of the BT Vision digital TV platform, said that rugby union was entering a "thrilling phase".
"We plan to bring the excitement of the very best matches to as wide an audience as possible," he said.
"We will also be bringing all of the action together in one place and will look to distribute it on a variety of platforms.
"BT is serious about sport and this deal means we will be offering the very best rugby action alongside some of the most thrilling football matches from the Premier League. That is a winning combination and one that will appeal to fans of both sports."
As well as showing live games, BT will also assist Premiership Rugby clubs, such as Leicester Tigers and London Irish, with any upgrades to their technical infrastructure at stadiums, and assist with community programmes.