Pete Marland will explain the 'enhanced partnership' between Labour and the Lib Dems on Monday.
Lib Dem leader Douglas McCall announced the groups' union on Saturday, which will keep Councillor Marland's Labour in control of Milton Keynes Council for a fifth year.
At the elections on May 3, Labour lost seats to the Conservatives, who became the largest party in Milton Keynes as a result.
However, Councillor McCall's decision to side with Labour for a third year means Mr Marland is set to remain as leader of the council - a decision the Conservatives have described as 'clinging on to power by their fingernails.'
When approached by the Citizen for comment, Mr Marland gave a brief outline of the situation, but said more would be revealed on Monday.
"After the elections, MK Council remained in No Overall Control," he told the Citizen. "No single party has a majority to form an administration without the support of another.
"After discussions between all parties, the Labour group and the Liberal Democrats have reached a decision in principle on the future leadership of MK Council.
"I will be making a further comment on Monday regarding the arrangements."