Willmott Dixon will fund the new Moberly Sports Centre in Queen’s Park through the development of 156 new homes on adjacent land.
The expanded leisure centre plans follow a public consultation which has seen the cost of the scheme rise from £17m to £19m.
The entire development, including the housing element, is worth around £60m.
The new Moberly Sports Centre will provide residents with two brand new swimming pools, a large sports hall and gym.
Councillor Steve Summers, Westminster City Council Portfolio holder for Community, said: “It’s a continuous, two-way flow of communication to ensure our plans receive support of the community.
“We will therefore be holding a third round of engagement events on the new plans this month to hear further thoughts on the detailed designs we have worked on ahead of planning application submissions later this summer.”
Construction is scheduled to start in Spring 2014.