Just been checking Wikipedia's article on The Passion and they had the names of some additional members of the cast, that I'd not heard previously. That in turn led me to look at the IMDb page for the film which now includes a quite lengthy cast list.
Perhaps the most well known member of the cast is James Nesbitt (Cold Feet, Millions pictured below) who will play Pontius Pilate. Back in July I mentioned that producer Nigel Stafford-Clark had taken the novel approach of using well known actors to play characters such as Pilate that would have been well known in their own time. That said I've not been able to find out who (if anyone) is playing Caiaphas, and it would appear that the previously unknown Mary the Mother of Jesus is being played by TV stalwart Penelope Wilton.The name I'm most excited by is Stephen Graham (This is England, Gangs of New York, pictured top) as Barabbas. Graham's performance in This is England was one of the best pieces of acting I've ever seen, and if he's able to bring to Barabbas the pent up anger he has so ably demonstrated in the past, then it will make his scenes something to behold.
Also fairly well known is David Oyelowo in the role of Joseph of Arimathea, a revelation that emerged from an interview with the Daily Telegraph. There are a couple of other newspaper articles which (very briefly) mention the appearance of these actors in this production. The Guardian has an interview with Penelope Wilton, and both the Belfast Telegraph and the Manchester Evening News have pieces on James Nesbitt.