Independence party Kanu has formally announced it will support President Uhuru Kenyatta's re-election bid in the August 8 general elections.
It is now expected that the Jubilee Party will work out an arrangement with Kanu ahead of the elections.
The announcement followed a closed-door meeting that lasted more than five hours and was attended by the party's top organ, the National Executive Council (NEC) on Thursday at Lake Nakuru Lodge.
Present in the meeting were party chairman and Baringo Senator Gideon Moi, secretary-general Nick Salat, nominated Senator Zipporah Kittony and West Pokot Senator John Lonyangapuo, among other NEC members.
The decision now dampens attempts by the National Super Alliance (Nasa) to work with Kanu, which still enjoys enormous influence in the vote-rich Rift Valley region.
In the past few months, Kanu has been seen to forge a working relationship with Nasa, with Mr Salat being seen in almost every meeting of the opposition alliance.
At a meeting held at the Bomas of Kenya in Nairobi, Mr Salat had announced that Kanu would support the opposition.
However, his sentiments were quickly dismissed by some party leaders, who called them personal.
A week ago, President Uhuru Kenyatta visited former President Daniel arap Moi at his Kabarnet Gardens home in Nairobi in a bid to seek his support.
The visit came days after the President’s mother, Mama Ngina Kenyatta, visited Mzee Moi at his Kabarak home in Nakuru.
Addressing journalists in Nakuru to announce the party's support for President Kenyatta, Senator Moi also announced that he will be defending his seat.