The cash injection is part of an £11.5 million ($18 million/€14.6 million) project to transform the venue which will boast a new entrance, spacious foyer and roof garden, the work for which is due to be completed in early 2014 before the Games begins.

Scottish Opera, which has owned the theatre since 1974, has been leading the campaign to find the necessary funding to carry out the work.

"Our vision is to open up the theatre to become a social hub," said the director of the Scottish Opera, Alex Reedijk.

"Somewhere people can gather with friends for great coffee during the day, enjoy outstanding performances, learn about the performing arts and discover the wonderful heritage of this beautiful theatre."

The theatre itself opened in 1867 and is the longest established in Scotland.

An artist's impression illustrating how the revamped Theatre Royal in Glasgow will look

Its auditorium was destroyed by fire in 1879 but rebuilt to the classical French Renaissance design seen today by renowned theatre architect Charles J Phipps and is now the largest surviving example of his theatre work in Britain.

"The Theatre Royal has delighted, educated and entertained generations of theatregoers," said the head of the Heritage Lottery Fund in Scotland, Colin McLean.

"It's fascinating history tightly interwoven with the social history and cultural traditions of Glasgow.

"We are delighted to add our support to a project which will not only put this national treasure on a world-class stage but along the way will inspire and involve people of all ages with memorable and rewarding experiences which will enrich their lives."

The £850,000 ($1.3 million/€985,100) boost means that 85 per cent of the funds needed for the revamp have already been raised, including £3.9 million ($6.2 million/€5.1 million) of capital funding from the Scottish Government alongside contributions from Creative Scotland, Glasgow City Council, the Heritage Lottery Fund, and an array of Scottish and UK trusts and foundations along with support from individual donors.

A public fundraising campaign to obtain the remaining funds will begin later this year with construction to begin this week.

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