The £50m project will see the two schools rebuilt on a new shared campus for over 1,000 students opening in September 2025.
Sports facilities including a fitness studio, swimming pool and 3G pitch will be available for use by the wider community.
Designed by Ryder Architecture, the building will also be the first net zero carbon in operation school in the county – keeping running costs to a minimum so more funding can be invested into teaching and learning.
Tony Fitzgerald, construction director at BAM, said: “We are really looking forward to working with Northumberland County Council to help deliver this exciting project.
“We are committed to ensuring we make a real positive social and environmental impact within the local community in Seaton Valley and can’t wait to get started on turning these plans into reality.”