Developer Abstract (Glasgow) said on-site works would start within the next few days on the 12-storey building, which will sustain around 250 construction jobs.
Planning permission for the 170,000 sq ft grade A office development, known as St Vincent Plaza, was granted in February last year.
Mark Glatman, chief executive of the Abstract group of companies, said: “We are delighted to confirm our move to start construction.
“We have been working hard over recent months to finalise various complex agreements to enable this work to commence and we are very pleased to be able to now move forward without any further delay.”
The speculative development has been designed by Glasgow-based Keppie Design.
Turner & Townsend is cost consultant on the job.
Glasgow Director, Andy Outram, said: “This appointment represents a massive success for Turner & Townsend and it is fantastic to see our expertise working on high profile Scottish projects recognised in this way.
“As one of the first truly speculative office developments for a number of years, St Vincent Plaza represents a fantastic opportunity for Glasgow’s regeneration, not to mention a return to health for the city’s commercial construction industry which has struggled in the current climate.
“I look forward to the commencement of construction and working to deliver Abstract’s goals through our expert guidance, planning, management and integration with the team.”