The development work will be completed ahead of the venue's 125th anniversary in December 2020, which will start a year-long celebration.
One of Northern Ireland's most iconic buildings, it was rescued from demolition in the mid-1970s, restored and reopened in 1980.
It was the first building in Belfast to attain Grade A listed status and is the only remaining Victorian theatre in Northern Ireland.
Its historic auditorium is regarded as among the architecturally most important theatre interiors in the UK and Ireland.
As part of the restoration and development project, the auditorium’s decorative paint and plasterwork will be repaired and restored, and seating, carpets, curtains and drapes will be replaced.
The theatre’s technical infrastructure will be upgraded, and customer facilities including those for customers with access needs will be improved.
The design of the foyer and public spaces will also be reimagined and a new bar will be installed in the glass extension overhanging Great Victoria Street. It is expected to attract thousands of visitors each year.
The principal contractor for the project, funded in part through the National Lottery Heritage Fund, is Tracey Brothers Ltd.
Ian Wilson, chief executive of the Grand Opera House said: “The Grand Opera House was last restored 40 years ago, and we are delighted that Tracey Brothers have been appointed to oversee this vital project.
“Between January and November of this year, thanks to the support of lottery players and the National Lottery Heritage Fund, we will restore the iconic and unique 1895 auditorium and transform the public areas of the building, including installing the first ever permanent exhibition to tell the fascinating story of the Theatre’s 125-year history."
The Grand Opera House was designed by the leading Victorian theatre architect Frank Matcham and completed in 1895.
Many of the world’s leading actors, singers, dancers and entertainers have appeared on its stage, including Charlie Chaplin, Sarah Bernhardt, Laurence Olivier, Vera Lynn, Luciano Pavarotti, Darcey Bussell and Laurel and Hardy.
Credit : Belfast Telegraph