Hillary Clinton will testify publicly on October 22 before a congressional panel probing the deadly 2012 attack on the US consulate in Benghazi, Libya, her presidential campaign says.
The attack left ambassador Chris Stevens dead, along with three other Americans, and has haunted Clinton as a policy-maker and presidential candidate ever since.
Clinton, who was secretary of state at the time, has been negotiating the terms of her testimony with the House of Representatives panel that is investigating the September 11, 2012 attack.
Campaign spokesman Nick Merrill on Saturday confirmed Clinton will testify in public session rather than behind closed doors.
Republicans have criticised the handling of the attack.
President Barack Obama's administration initially said the attack was the spontaneous act of a mob enraged by a video circulating on the internet that insulted Islam.
But days later the administration changed its version of events and said the attack was an act terrorism.
Obama was up for re-election in less than two months' time. And critics said the initial account - mob violence rather than a premeditated terror attack - sought to mislead the public and avoid angering American voters worried about terrorism.
The State Department has started releasing emails from Clinton's time as secretary of state, and some of them deal with the Benghazi attack.
That correspondence is politically sensitive for Clinton too because she has admitted using a private server and email address during her time as the top American diplomat from 2009 to early 2013.
The Justice Department said on Friday it has been asked by internal inspectors to consider opening a formal probe of Clinton over that, on grounds she may have mishandled classified information.