Two-part drama Paper Giants: The Birth of Cleo, which tells the story of the magazine editor Ita Buttrose revolutionising the Australian women's magazine industry, was a massive success when it aired earlier this week.
The first episode on Sunday night was the most watched show in its timeslot with 1.2 million viewers, while the second instalment got an audience of 1.34 million.
ABC1 controller Brendan Dahill said: "We had hoped that Paper Giants would appeal to a wide audience and we are thrilled they have not only taken one bite, but came back in greater numbers for second helpings on Monday night.
"But for us, it isn't about ratings. We screened Paper Giants outside the official ratings period so the Australian audience had something to look forward to when the commercial networks were taking a break."
It is believed that the show, which also stars Rob Carlton as Kerry Packer and Tony Barry as Sir Frank Packer, will air again on Easter Sunday on ABC2.
Keddie was recently nominated for a Silver Logie award for her role in comedy drama Offspring, which she has previously referred to as "eccentric", "unpredictable" and "surprising".