High street giant Topshop has ploughed millions into its Buchanan Street and Argyle Street shops.
Topshop bosses will unveil the Buchanan Street branch tomorrow, with the official launch of the Argyle Street store on April 17.
That store, next to Debenhams and HMV, has been in Glasgow for about 25 years and has grown by a third under expansion plans.
Work has been going on since January and it is hoped the finished package will help to push Glasgow closer to the level of Topshop's store in Oxford Street, London. That branch covers five floors and attracts up to 30,000 customers every day.
Donnie Campbell, the company's area manager, said: "Glasgow has always been amazing for Topshop and Topman and for a long time we have wanted to give our customers an even better brand offer.
"The dual site relaunch at Easter is going to be one of the brand's biggest investments this year, with a 40% growth in space and products across both stores.
"Glasgow is one of the most important cities in Scotland, showcasing the best brands in Britain."
Insiders said the investment by Arcadia, which owns a string of brands, including Topshop, Topman, Miss Selfridge and Dorothy Perkins, has shown its commitment to Glasgow's high street.
Among the changes to the Argyle Street shop is a personal shopping suite double the size of the original. The top area of the ground floor will be used for providing style and shopping advice.
Topman's retail space is also expanding and Miss Selfridge will be opening in the basement, offering customers the chance to shop across several brands in the one store.
The Buchanan Street store, which has been at the top of the street for about 15 years, is expanding from two floors to three after Topman, which was formerly in the basement, moved out.
That Topman was relocated last year and now shares shop space with another Arcadia men's brand, Burton, in the former Dorothy Perkins/Burton store at the corner of Buchanan Street and Sauchiehall Street.
Topshop bosses say the revamped stores will be receiving the pick of their collections.
The Boutique range and Topshop Beauty, as well as specialised denim and shoe lounges, will be part of the new setup. The latest Kate Moss Collection, which launches at the end of the month, will also be included.
The investment has been welcomed by fashion experts.
Mary McGowne, founder of the Scottish Style Awards, said: "This is fantastic news for Glasgow and again reinforces the city's status as the UK's premier shopping destination outwith London.
"It speaks volumes about the healthy state of city-centre shopping in Scotland's style capital - it's a massive vote of confidence.
"While high streets across the country struggle to compete with online shopping, this demonstrates a real bucking of the trend."