Details have today (1 July 2011) been officially announced for the 25th anniversary concert celebration of Andrew Lloyd Webber's The Phantom of the Opera, which will take place at London's Royal Albert Hall on the weekend of 1 and 2 October 2011.

Three concert performances have been announced with a single performance on Saturday evening and two shows on Sunday. Tickets for Phantom of the Opera at the Albert Hall will go on sale at 10am on Monday 4 July 2011.

As previously reported, Whatsonstage.com Award winner Ramin Karimloo will take the title role in the special concert, with producer Cameron Mackintosh today confirming that Karimloo will appear alongside Sierra Boggess as Christine. They will be joined by Barry James as Monsieur Firmin, Gareth Snook as Monsieur André, Liz Robertson as Madame Giry and Wynne Evans as Piangi and a cast and orchestra of over 200.

Casting for the roles of Raoul, Meg Giry and Carlotta Giudicelli is still to be announced. Special guest appearances are also promised.

Phantom of the Opera at the Albert Hall will be directed by Laurence Connor with, as previously tipped, the show's original choreographer Gillian Lynne.

Karimloo played the masked man at the West End's Her Majesty's Theatre from 2007 to 2009 before taking the same role in the musical's sequel Love Never Dies originally opposite Boggess, when it premiered at the Adelphi Theatre in March 2010. The sequel, which he continues in until the end of its run on 27 August 2011, earned him this year's Whatsonstage.com Award, and an Olivier nomination, for Best Actor in a Musical.

Karimloo - who also appeared as Enjolras in the 25th anniversary concert of Les Miserables last year - appeared to let the cat out of the bag, sharing details of the Phantom concert as part of the Comic Relief Twitter celebrity auction #TwitRelief in March and in an interview with The Stage newspaper in May.

Speaking about concert, producer Cameron Mackintosh today said in a press statement: "It is amazing to think that the extraordinary success of The Phantom of the Opera is about to celebrate 25 years. The success of the show has become the stuff of theatrical legend so Andrew and I felt we needed to create a really special performance to celebrate the 25th anniversary.

"One of the great strengths of The Phantom of the Opera is that being set in an opera house, its production is totally theatrical. So we felt that there could be no better 19th Century theatrical auditorium in London for this occasion than the Royal Albert Hall."

The concert production will be designed by Matt Kinley inspired by Maria Björnson’s original design. Lighting is by Patrick Woodroffe and Andrew Bridge with sound by Mick Potter.

The Phantom of the Opera, which is directed by Harold Prince, has now been seen in 124 cities in 25 countries and played to over 100 million people. The musical is based on Gaston Leroux's gothic novel about a disfigured masked man who falls in love with an ingénue singer at the Paris Opera House.

The show premiered on 9 October 1986 at Her Majesty’s, where it continues to run. The original cast featured Michael Crawford (currently in the title role of Lloyd Webber's revival of The Wizard of Oz) as the titular character alongside Sarah Brightman as Christine and Steve Barton as Raoul.

The second longest-running musical in West End history after Les Miserables, Phantom is currently booking at Her Majesty's until 8 April 2012, but has a short gap in its booking period during its birthday week from 7 to 10 October 2011.

Love Never Dies, which premiered in London on 3 March 2010 (previews from 20 February) and recently had its Australian debut in Melbourne, is set ten years after The Phantom of the Opera. In it, Christine, now a huge star and married to her old flame Raoul, is lured to sing for the Phantom once more, this time at his pleasure palace on New York's Coney Island.

Phantom has also been tipped for an international tour in the new year, while a year-long UK touring production is expected to launch from the Theatre Royal Plymouth in March 2012. The musical's plans follow the success of Les Miserables' 25th anniversary tour. The projects could share a director in Laurence Connor, as well as producer Cameron Mackintosh.

Tickets for Phantom of the Opera at the Albert Hall go on sale on Monday 4 July 2011 at 10am and are available on 0845 401 5045 or at www.phantom25th.com (Note: It is expected this website will go live at 2pm today, 1 July).