The four-year contract will see BSkyB and ESPN, who currently split coverage of matches, replaced by BT as the only platform on which to watch top flight English club rugby.
In a further development, BT will also have exclusive live broadcast rights to games played by Premiership teams in European competitions from 2014 for three years.
This could potentially result in the fragmentation of European coverage if BSkyB continue to hold overall rights to any competition, although the landscape may have changed significantly by then.
The qualification process for the Heineken Cup is to be discussed at a meeting between ERC stakeholders in Dublin next Tuesday.
The English and French clubs are currently in dispute with ERC over its structure and have threatened to set up an alternative tournament when the current agreement ends in 2014 if their demands are not met.
"This is a game-changing agreement and will deliver a service that I know our club supporters will enjoy," Premiership Rugby chief executive Mark McCafferty said.
"We are delighted to have concluded our discussions with such an ambitious partner that will help bring the Premiership to new audiences."
The agreement sees BT secure broadcast rights to up to 69 Premiership matches per season and also includes games from the entire J.P. Morgan Asset Management Sevens Series.