Chivas Brothers, makers of whisky and gin, have added to the £750,000 in donations the art school (GSA) revealed it had received last week for the fund to restore Charles Rennie Mackintosh's architectural masterpiece after a devastating fire in May.
The Mackintosh Appeal, launched by the Glasgow School of Art Development Trust on June 18, has trustees including Peter Capaldi, Bryan Ferry and the leading Hollywood actor Brad Pitt.
The appeal hopes to raise £20 million - the Scottish Government has said it will provide up to £5m in matched funding to support the GSA in its recovery, and the UK Government also recently said it would give £5m to The Mackintosh Appeal.
Laurent Lacassagne, chief executive and chairman of Chivas Brothers, part of Pernod Ricard, visited the GSA and yesterday announced the donation.
He said: "The terrible news of the fire at Glasgow School of Art was heard all over the world and greatly saddened my colleagues and I, not just in Scotland, but globally.
"Supporting our communities and artistic development are values we hold dear at Pernod Ricard. We are delighted that through this donation we are contributing towards the development trust, and look forward to seeing this prestigious institution and iconic building restored to its former glory very soon."
Chivas Brothers, first established in 1801, is a leader in Scotch whisky and premium gin and its drinks include Chivas Regal, Ballantine's, Beefeater Gin and The Glenlivet.
Alan Horn, director of development at the Glasgow School of Art said: "We have been overwhelmed by the emotional, practical and financial support the GSA has received since the sad events of May 23.
"This generous donation from Chivas Brothers will help our students, who are the beating heart of the GSA, and the institution to recover from the impacts of the fire."
Last week the musical impresario Sir Cameron Mackintosh gave £250,000 towards the rebuilding of the Mackintosh Building and the GSA has also received donations from the Hugh Fraser Foundation and £150,000 in individual donations.
The Hugh Fraser Foundation, a long-term supporter of the GSA, has pledged £300,000.
The fire destroyed much of the west wing of the famous building.
Although firefighters managed to save most of the building's structure and 70 per cent of its contents, many students were severely affected when they lost work prepared for their Degree Shows.
Professor Tom Inns, director of the GSA, said last week: "I would also like to extend the heartfelt thanks of the Glasgow School of Art to all the institutions and individuals who have donated to the appeal to date."