Boris Johnson and Jeremy Corbyn will go head to head for the first time in a televised election debate on Tuesday 19 November.
After challenging the prime minister to one earlier in the week, the Labour leader said it was "welcome" that Mr Johnson had accepted.
He was accused of running scared from TV debates by former rival Jeremy Hunt during the Tory leadership race following the resignation of Theresa May in June.
Mr Johnson did eventually take part in two one-on-one debates after facing great pressure to do so.
Mr Corbyn has called the 12 December vote a "once in a generation election" - and claimed on Twitter that "the choice could not be clearer."
He said it was down to: "Boris Johnson's Conservatives protecting the privileged few - or a Labour government on the side of the many".
The prime minister also took to Twitter to comment on the debate, saying he was: "Looking forward to making the positive case to the country that we should #GetBrexitDone and deliver on the people's priorities - #OurNHS, schools, tackling crime and the cost of living."
But the Liberal Democrats and the SNP are not happy about their omission from the debate, which will be shown on ITV.
Jo Swinson's party has claimed her rivals are "running scared of debating the woman leader of the strongest party of Remain" - and suggested the broadcaster "shouldn't help them to stitch up the debates".
The Lib Dems' official Twitter account also said: "We do not live in a two-party system and the upcoming ITV election debate should reflect that".
It also set up a petition calling for its leader to be able to join the discussion.
Senior Lib Dem MP Chuka Umunna was equally outraged, saying: "Whatever your politics, this is discriminatory, undemocratic and wrong.
"Not only is it two blokes deciding to have a debate excluding women, we are not a two party country and the sizeable proportion of the public who want to #StopBrexit won't have a voice in the room."
The SNP Westminster leader Ian Blackford claimed the debate would be "deeply misleading for audiences."
He said: "The SNP may well hold the balance of power in the next parliament.
"If Boris Johnson and Jeremy Corbyn think they are good enough to be prime minister, then they should be up to debating the SNP."
ITV has said details of further multi-party debates would be announced in due course.