Kabete MP Ferdinand Waititu has been endorsed to fight it out with Governor William Kabogo for the Jubilee Party ticket in the primaries.
Four other gubernatorial hopefuls dropped their bids and agreed to back Mr Waititu against Mr Kabogo. The Jubilee Party primaries are slated for next month.
The five who have formed an alliance dubbed 'United for Kiambu' made the announcement on Sunday at Kimende shopping centre in Lari during a rally.
The announcement ended months of speculation that they were planning to support one of them to face the incumbent in the primaries.
The aspirants said they decided to swallow their pride and back one of them in order to bring change in the county, which they said was not heading in the right direction.
They announced the line-up indicating the positions each will get if elected in the August 8 General Election.
In the new deal, James Nyoro will be Waititu's running mate. Mr Nyoro vying on a National Alliance Rainbow Coalition (Narc) was trounced by Kabogo in the 2013 elections.
David Ngari commonly known as Gakuyo will head the newly created position of chief minister where he will be in-charge of all the county executive committee members (CECs). He will also head the Lands department.
John Mugwe, an engineer by profession, will be the Roads executive while Aquiline Njoki will be the Trade and Legal Affairs executive.
Under the deal, it was agreed that Waititu will be dealing with political affairs while Mr Nyoro and Mr Gakuyo will be spearheading the county's development and economic agenda.
The Kabete MP said the team meant well for the county and they were confident of clinching the JP ticket in the primaries.
He said the team was determined to bring change, claiming that the Kabogo administration has little to show for the time it has been in office.
"There is nothing much to show on the ground despite the county receiving about Sh40 billion for the past four years from the exchequer and we are now telling Kabogo to start packing his things since his goose in now cooked," Waititu said.
The MP said to enhance development, they will create a Ward Development Fund from where money from the county government will be channelled for various projects.
"Through this fund, the residents will now have a say on which development projects they want given priority," said Waititu.
Nyoro said the team's primary goal, if elected, will be to make Kiambu a success story that will be emulated by many other counties.
He said the team will work under the guidance of five pillars which include fighting extreme poverty, reviving agriculture and improving health services, creating employment for the 500,000 jobless youths and building roads and markets.
He said their administration will put in place a lot of emphasis on reviving the county's dwindling agricultural sector.
"About 1.2 million county residents are farmers but they have nothing to show or smile about despite agriculture being a devolved function. We will ensure the farmers are happy and satisfied by making sure they get market and good prices for their produce," said Nyoro.
Gakuyo, who is the overseer bishop of Calvary Chosen Centre, said the church cannot afford to be silent as the county continues to sink.