Amid mounting speculation that Duceppe is working behind the scenes to replace her, Marois wasted little time in flashing her defiance at a news conference called to show off a PQ candidate for the next election.
"Mr. Duceppe said he was confident that I would make the right decisions — and that decision is made," she said straight off the bat.
"I will assume my responsibilities right until the end as leader of the Parti Quebecois.
"What does that consist of? It consists of offering an alternative government to Quebecers, presenting a solid team ready to govern, a team of men and women motivated by their convictions."
Then she introduced future candidate Daniel Breton.
Earlier this week, Duceppe said he was "convinced that party (PQ) members and their leader will make the right decisions for Quebec's future."
The comment was widely interpreted as a clear signal that Marois should step down to help the sovereignty movement.
One published report said Marois even called Duceppe and asked him whether she could state publicly that he was not interested in the leadership.
He reportedly told her she couldn't say that.
Marois confirmed Friday she spoke with Duceppe during the week and invited him to join the party.
"I can tell you very clearly that he assured me he would respect my choice," she said.
"The door is always open for all sovereigntists. We will never be stronger than when we're united. I'm inviting Gilles and all sovereigntists to join our party."
Duceppe told The Canadian Press on Thursday there is no organization in place to promote any run at the leadership.
"Nobody is working on the ground for me," he said.
Although Marois received 93 per cent support in a leadership vote last spring, she has not had an easy year.
Several PQ members of the legislature quit over her leadership, another raised the possibility of the party disappearing, and Marois has been unable to make much of an impression in opinion polls.
Premier Jean Charest has until the fall of 2013 to call an election.