The hard-hitting thriller stars Lennie James as charismatic but controversial cop Tony Gates and will debut on Tuesday, 26 June at 9pm.
Vicky McClure (This Is England), Martin Compston (The Damned United) and Neil Morrissey (Men Behaving Badly) will also star.
Line of Duty has been created by Jed Mercurio, known for his work on Bodies and Strike Back.
"I've always been a fan of thrillers that twist and turn and pull the rug from under your feet," said Mercurio. "I love dramas that rush headlong and then lurch off in some totally unexpected direction.
"For a long time, I've also been interested in creating a police series. We agreed that, in keeping with my medical dramas - Bodies and Cardiac Arrest - whatever we did would have to break the mould. It would have to be full of moral grey areas and populated by antiheroes."
The writer added: "Line Of Duty is first and foremost a thriller. But it's also a revisionist commentary on 21st-century policing."
> Gina McKee, Neil Morrissey, Vicky McClure join BBC Two's Line of Duty
Watch the trailer for Line of Duty below: