Actor and director Ellie Swann said the space in the historic Dunedin building would reopen in August as the "New Athenaeum Theatre".
The initiative comes after Swann was unable to find the space she was looking for in the warehouse precinct.
Last year she told the Otago Daily Times she was planning a not-for-profit theatre with two performance spaces and seating for about 120 in the Vogel St area.
She said the city needed another theatre because the Globe had a specific purpose of developing people’s interest in theatre, and concentrated on producing a schedule of plays.
Getting a spare space there, or at the Fortune Theatre, could be "a real issue", and could be out of reach financially for some.
Ms Swann said this week her dream of a theatre in the warehouse precinct had not come about because she was unable to lease the space she wanted.
But a real estate agent had put her in touch with Athenaeum owner and heritage developer Lawrie Forbes, who said she could use the theatre.
Mr Forbes said he understood the theatre was set up by the Otago Cinema Club, whose initials were still on the door.
The theatre was also the birthplace of the Fortune Theatre, and had since been used for drama courses; by the Globe when that theatre was being renovated; and by the Dunedin Fringe Festival.
Ms Swann, who has set up a trust to raise money, said the New Athenaeum Theatre would be a "fully flexible" space for performers to use.
The theatre would also provide expertise to performers who needed it, and would include a rehearsal space.
Some fixed seating would remain, but the rest would be removed and replaced with movable seating.
She said while not being able to find a home in Vogel St was "really disappointing at the time", the Athenaeum was a silver lining.
The next step was to get people from the theatre and performance community to help out with working bees to "freshen up and modernise" the space so it was ready to use.
"The investment will be people-powered," she said.
Mr Forbes said he would also be doing maintenance to that end.
Ms Swann said the theatre would continue for the next two years, and after that she and Mr Forbes would assess how it had gone, and decide on the future.
