A new hotel, food market and office and retail space will make up the new Clerys Quarter in Dublin city centre.
Work on transforming the site of the former department store is expected to begin in the next few months.
A number of features will be restored, including the iconic Clery's clock, staircases and the façade.
400 jobs are expected to be created, in addition to the temporary employment of 750 construction workers.
The building's new owners, Europa Capital, are promising it will become a "world class retail, office and leisure destination".
The building was bought for €29m and last year the new owners got permission to extend the buildings from 212,000 sq ft to 344,000 sq ft.
A tendering process for contractors is underway, with construction due to being in the first quarter of this year.
The development is scheduled for completion in late 2020.
Commenting on the new proposals, CEO of DublinTown, Richard Guiney said: "DublinTown very much welcomes this proposal for the Clerys site. This mixed-use development is in keeping with our Dublin One Vision for the area. We see a development like this, including high-end food and beverage, office space and retail, being exactly what the district needs.
"Once complete, the office workers and staff will become increasingly important to the local economy. We look forward to seeing the site complete in 2020," he added.