ODM leader Raila Odinga on Friday met and held talks with retired president and his former coalition partner Mwai Kibaki.
The agenda of their surprise meeting, which comes a month after Mr Odinga's handshake with President Kenyatta, was not immediately clear.
Mr Odinga is accompanied by his legal adviser and co-chairman of the team drawing up the terms of reference of the handshake deal, lawyer Paul Mwangi.
"Raila is going to meet the retired president," Mr Mwangi told the Nation on phone without giving further details.
The Nation, however, independently learned that Mr Odinga would brief the retired president on his new engagement with President Kenyatta.
"It is about the handshake, a lot is going on and he wants to brief Mzee Kibaki as much," said a source close to the opposition leader.
The meeting comes only a week after Mr Odinga held similar talks with Mzee Kibaki's predecessor, retired president Daniel Moi, at the latter's Kabarak home in Nakuru County.
Earlier Friday, Mr Odinga hosted Nairobi Governor Mike Sonko at his Capitol Hill offices.
The meeting took place at the request of the governor.
Mr Sonko congratulated Mr Odinga and President Kenyatta for agreeing to work together and unite the country.
He expressed support for Mr Kenyatta's and Mr Odinga's initiative dubbed Building Bridges to a New Kenyan Nation.
The two leaders discussed the state of the city county, the challenges facing the management and prospects.
Mr Sonko singled out garbage management as the single biggest challenge facing his administration but said he had put in place measures to address the challenge.