Sophia Myles and Laila Rouass are joining the cast of ninth series of Spooks, which has just started filming in London.

The new series of Spooks will introduce a host of new characters who shake things up and give cause for concern as Section D, once again, are left wondering exactly who can really be trusted.

Friendships will be tested and the depth of deceit will lead to an unprecedented game of cat and mouse for the Spooks.

As well as Sophia and Laila, Max Brown (Mistresses, The Tudors), Iain Glen (Lara Croft: Tomb Raider) and acclaimed theatre actor Simon Russell Beale will join Spooks as series regulars. But the characters they play and the impact they have on the team dynamic is being kept tightly under wraps.

BBC Executive Producer Sarah Brandist said: “We are very proud to introduce an extraordinary number of exciting new characters to this new series. The new additions will really ruffle some feathers but, as intrigue and betrayal is at the heart of the new storylines, we don’t want to give too much away at this stage. All will be revealed when the series transmits on BBC One later this year!”

Spooks will screen on BBC One later in 2010.