Preston City Council now has £2.7million to help restore and revamp both the Grade II-listed Avenham Park and its rundown neighbour - Miller Park.
The new pavilion, which will house a café, classroom, WC facilities and a ranger's base, is to become the centrepiece of this £4.9 million regeneration of the city's parks.
The timber-roofed structure will also feature an external performance space and a crescent-shaped terrace overlooking the River Ribble.
Earlier this year the south London-based firm saw off challenges from 67 practices, including Studio Egret West and Niall McLaughlin Architects, to win the RIBA-run contest.
Speaking about the funding announcement, councillor Veronica Afrin, an executive member for regeneration, community and leisure services, said: 'I'm absolutely thrilled we have successfully secured this grant.
'The project will not only provide better facilities for visitors to the parks, it will increase safety and enhance this beautiful city-centre oasis.'
Work is expected to begin on site early next year.