Full casting has been announced for the Les Miserables 25th Anniversary concert at the O2 Arena on 3 October, which has added a matinee performance due to "extraordinary public demand".

Newly announced cast members are Ramin Karimloo (currently playing The Phantom in  Love Never Dies), who will play Enjolras, and Samantha Barks (currently playing Eponine at the Queen’s Theatre) who will play Eponine.

They join the previously announced company of over 300 actors and musicians, including Alfie Boe (Jean Valjean), Nick Jonas (Marius), Norm Lewis (Javert), Matt Lucas (Thénardier), Lea Salonga (Fantine), Jenny Galloway (Madame Thénardier), Camilla Kerslake (Cosette) and the casts of the original production at the Queen’s Theatre, the new 25th anniversary production at the Barbican, and members of the original 1985 London cast. 

Cameron Mackintosh said today: “Our latest Eponine at the Queen’s, Samantha Barks, who I first met as a hugely talented finalist in BBCTV’s I’d Do Anything ... has proved to be such as success performing with Nick Jonas and Camilla Kerslake, that we just had to have her for the concert.

"To play Enjolras, I am very grateful to Andrew Lloyd Webber that he has kindly agreed to let his star of Love Never Dies, Ramin Karimloo take a night off to play Enjolras - a role he had a huge success with several years ago."

Mackintosh also announced that due to an "amazing" public response the 7pm concert has sold out, so a 1.30pm matinee has now been added.

The concert will be staged by the same team behind the 25th anniversary production: directors Laurence Connor and James Powell and designer Matt Kinley, with original costumes by Andreane Neofitou, additional costumes by Christine Rowland, lighting by Patrick Woodroffe and Paule Constable and sound by Mick Potter.

In other Les Mis casting news, the original production at the Queen’s Theatre will welcome Norm Lewis as Javert from 5 July and X Factor’s Lucie Jones as Cosette from 12 July 2010.

Nick Jonas has also extended his run as Marius in the show for an extra two weeks until 24 July, due to a recent change in the Jonas Brothers world tour schedule that will now start at a later date. Alistair Brammer returns to the role of Marius from 26 July.