The Government will invest pound;13 million in the new school, which is expected to open in the Kensington and Fairfield area of Liverpool in 2005.
It will be the 10th jointly-backed church school in the country but the first opened as a new-style city academy, state-funded but independent of local authority control.
Plans for the new church academy were rubber-stamped just weeks after the controversial closure of the joint Anglican-Catholic St Augustine's school in Oxford - a casualty of school reorganisation in the city.
The Bishop of Liverpool, James Jones, who has been behind the project for the last four years, said: "We came up with the idea round about the same time that the Government's city academy initiative was launched.
"We had to find sponsors and BT and Marconi were all ready to go - but the stock market turned and we were left alone. Fortunately the archdiocese were able to become co-sponsors and it has progressed.
"Each church has its own director of education and they have worked closely with Liverpool City Council on the school. We hope to appoint a new board of trustees, who will in turn appoint governors and then a new head by autumn 2004. The school will be a symbol of regeneration in that area of the city."
A further pound;2m will be invested in the academy by the Catholic and Anglican churches. The new academy, for 900 pupils, will be built on a site near the city's Newsham Park. Our Lady's RC high school in Kensington will close under the plan, and its pupils will go to the new academy. Anglican pupils would be drawn from other secondary schools, with Kensington children given priority.
The country's first joint church school, Cuthbert Mayne comprehensive in Torquay, opened in the mid 1970s. St Michael's, Barnsley, became the latest jointly-run school to open last year.