The Birmingham offices of big four accountancy firm Deloitte will undergo a multimillion-pound refurbishment.
The news comes after the business signed a new ten-year lease on the base in Four Brindleyplace where its 750 staff occupy three floors.
The refurbishment is expected to take 12 months.
Pauline Biddle, practice senior partner for Deloitte in the Midlands, said: "Over the last few weeks, due to the public interest in the opening of Grand Central, millions of people have seen what we have known for some time.
"Birmingham is now competing on a global scale for investment, talent and tourism, rivalling not just London but cities across Europe and beyond.
"Deloitte has a thriving and exciting practice here in the Midlands and it is time for us to ensure we have an office not just fit for purpose but fit for the future.
"The Deloitte UK board has recognised this and supported us with significant investment that will benefit our clients and our people."
The announcement comes as the firm, which has been based in Brindleyplace for 14 years, has just welcomed more than 70 new starters to its Midlands practice via its graduate and BrightStart programmes.