Barr Construction has been announced as the main contractor for the revamp of Ashton Gate Stadium in Bristol.
Home to Bristol City since 1904 and Bristol Rugby from August 2014, the 21,500-seater stadium can now begin a two-year redevelopment project.
Costing £45 million, the rebuild will see the capacity of the ground increase to 27,000 with work to the Wedlock, Dolman and Williams stands.
Bristol Sport chairman Martin Griffiths said: "It is hugely exciting to know that the stadium work is under way.
"It will have the very latest technology to ensure everyone visiting has the best sporting and entertainment experience in the South West."
The first stage of a three-phase plan will see the 86 year old Wedlock Stand demolished and then rebuilt with conference facilities, administration offices, a sports bar and shops.