“Both President Salva Kiir and Dr Riek Machar are coming to Addis Ababa for talks, they are coming now and should meet today,” Ethiopian foreign ministry spokesman Dina Mufti told international news agency AFP confirming the development.
Machar had previously demanded 11 detainees accused of being co-conspirators in the coup plan be freed before negotiations.
He denies there was a plot – alleged by his rival President Salva Kiir.
Regional leaders at the Inter-Governmental Authority on Development (IGAD) had set December 31 as a deadline for face-to-face talks between Kiir and Machar.
Ugandan President Yoweri Museveni on Monday warned Riek Machar to comply with a ceasefire deal ending Today or face action by regional nations.
In an interview on the same day, President Kiir ruled out any power sharing with Mr Machar to halt violence that has killed at least 1,000 people in the last two weeks.
“These men have rebelled. If you want power, you don’t rebel so that you are rewarded with the power. You go through the process,” he said.
Mr Kiir has consistently refused to release Mr Machar’s political allies, arrested when he made the coup plot allegations.
The IGAD deal agreed in Nairobi on Friday said only that leaders would “consider taking further measures” if hostilities did not cease within the timeframe.