COLCHESTER High Street is set to be closed for a weekend as part of the redevelopment of Williams and Griffin store.
The award-winning Fenwick store is undergoing a £30 million upgrade which will see its retail space increase from 63,000 sq ft to 85,000 sq ft.
A 350 tonne crane will be needed to carry out part of the work.
The store is to apply for permission to close the High Street to traffic for one weekend so the crane can be brought in.
Williams and Griffin's new managing director Carl Milton said: "We are excited with the redevelopment and this private investment presents a high level of intent in Colchester.
"It will hopefully be a halo for other private investment in the town."
He added: "We know the importance of the store to the town and we know we are changing history but we do believe this work is for the better."