Jeremy Corbyn and Owen Smith will go head-to-head in a husting for the first time next month.
The two leadership conteders will meet in Cardiff on 4 August, party general secretary Iain McNichol confirmed.
In an email to members Mr McNichol stressed that members would be choosing the party’s “candidate for prime minister” and that the hustings would help them decide.
The dates of televised hustings events are expected to be announced in due course by broadcasters.
“The Tories have failed working people over the last six years and now in choosing Theresa May who has been at the heart of the Tory Government since the beginning, they have chosen more of the same failed approach,” he said.
“Labour members and supporters will now select a candidate for Prime Minister who can offer the change working people and Britain needs.
“We need a Labour government again to stand up for Britain and what we believe in: building a strong economy, defending our NHS and our public services, and fighting for fairness, equality and social justice.
“The leader you choose in this contest will be Labour’s candidate for Prime Minister. They will lead Labour into the next General Election to fight for the change we need.”
The announcement comes amid a High Court battle over whether Mr Corbyn should be automatically included on the Labour leadership ballot paper.
A suit from a Labour donor argues that Mr Corbyn should seek nominations, as challengers have had to.
However Labour ruling National Executive Committee ruled earlier this month that Mr Corbyn should automatically be on the ballot paper as the incumbent.
