Pauline Marois of the Parti Quebecois, the Liberals' Philippe Couillard, the Coalition for Quebec's Future's Francois Legault and Francoise David of Quebec solidaire will square off on the TVA network for two hours on March 27.
It will also be broadcast on the French-language network's all-news LCN channel, financial channel Argent and on tvnouvelles.ca.
Marois had originally said she would only participate in one debate. TVA is owned by Quebecor, whose majority shareholder is Pierre Karl Peladeau, who resigned as CEO to become a star PQ candidate.
The TVA debate will focus on four themes: public finances, identity, social policy, and governance.
The other debate will be broadcast on Radio-Canada and Tele-Quebec on March 20.