The opening takes place on June 16, two days after the 11th anniversary of the death of the blues and rock legend.
The news comes following a two-year debate with the city council regarding planning permission.
The National Photographic Archive voiced objections on the grounds that it would “impact on their identity". However a petition in favour of the replica was signed by over 3,000 people.
Monument organiser Mark Walsh said: ”Rory was our first international rock and blues star. He is still hugely popular. It is very important that we recognise his vast contribution to modern music.”
A large open air concert is being planned for the unveiling of the replica.
Rory Gallagher will also be commemorated at the Rory Gallagher International Tribute Festival, held in his brithplace of Ballyshannon, from June 1-4.
Festival organiser Barry O’Neill said that over two thousand people are expected to come.
"Rory's fans are travelling from Australia, Canada, the US, Greece, Germany, Italy, Holland, Norway and throughout the UK and Ireland."