The Birmingham Development Company has been given the green light by city planning officials to build The Cube - the final phase of The Mailbox development.
Work on the futuristic building is scheduled to start next spring.
Alan Chatham, director of Birmingham Development Company, said yesterday: "Since we announced the national design competition back in April for the final phase of The Mailbox, it has been a hectic few months to get to this stage in record time.
"Now, to begin December with permission to bring a building of this calibre to Birmingham is just fantastic. We are thrilled that the city has recognised what we are trying to achieve with The Cube - a building truly incredible both in its structure and content."
He added: "What has been accomplished to date in the city's regeneration has been nothing short of amazing, yet we hope to set a new benchmark for developments in Birmingham.
"The Cube will bring forward a new standard of architecture and a building which will not only be Birmingham's most striking waterside location, but also one which is identifiable around the world."
The building, with a value of over £100 million, has been designed by internationally renowned architects MAKE, also commissioned for the new Digbeth Coach Station.
Led by Ken Shuttleworth, formerly of Foster and Partners, the design team has created a 17- storey cube aimed at providing a spectacular contrast to the increasing number of towers on the Birmingham cityscape.
Inside, a stunning open atrium which twists as it climbs the height of the 450,000sq ft building will be lined with coloured glass and combined with an exterior clad in shimmering metallic fretwork, the building has visible links to Birmingham's heritage in engineering and jewellery manufacture.
Uses for the mixed-use building include the city's first rooftop restaurant, plus a boutique hotel and residential apartments with internal views over the twisting atrium. Further down, high specification Grade A office space is planned with more exclusive retail and waterside restaurants at the base.
Agents have already been appointed to cover the mix of uses with Knight Frank Birmingham taking calls on the residential apartments, and DTZ and GBR acting as joint letting agents for the offices.
Retail specialists, Markham Vaughan Gillingham, are working on the retail and restaurant elements, Knight Frank's London office is appointed for the hotel and CBRE is acting as strategic planning consultants.
Transforming what is currently a predominantly derelict site adjacent to The Mailbox - The Cube is expected to encourage new investment into the area of the city, much as The Mailbox triggered a myriad of residential developments in and around the area after opening in late 2000.
Leader of Birmingham City Council, Coun Mike Whitby said: "The Cube breaks all the boundaries of what has been achieved in Birmingham so far.
"Our city is a city of the future and as a futuristic building with phenomenal foresight in style and design, it is indicative of our plans in how we see Birmingham developing.
"The Mailbox has already raised the bar in the quality and calibre of our architecture and retail offering, the worldwide brand names and stylish restaurants have given Birmingham a contemporary profile rivalling the capitals of Europe. The Cube will help to elevate us onto a global stage."
The building is to be located between The Mailbox caf> bars and restaurants, Washington Wharf apartments, Commercial Street and the Birmingham Worcester canal.
Birmingham Development Company is aiming to begin demolition and enabling works in 2006, with overall completion scheduled for 2008.