Given how busy Luther star Idris Elba and series creator/head writer Neil Cross have become since the show launched, it’s not surprising that we’ve had a bit of a wait for new cases. But filming on four new episodes began this week and now comes word that Sienna Guillory has signed on.

According to the BBC, the four hour-long episodes will see our taciturn hero back under pressure as he investigates two conflicting crimes and fends off an ex-copper determined to bring him down (he gets that a lot, we note).

Guillory is set to play Mary Day, who works in a vintage clothes shop and encounters the world’s grumpiest DCI in a chance encounter. While she’ll cosy up to John Luther, it’s all but guaranteed that things won’t run smoothly. Besides, what will Alice think? Assuming Ruth Wilson returns, that is…

“You realize why Luther is so good when you read Neil Cross’ scripts, and then you meet Idris and understand what ‘untamed’ means” says Guillory. “There is no other set I’d rather be on, and I love the disastrous fun of being Mary Day, the right girl in the wrong place.”

She joins a cast that includes returning veterans Warren Brown, Nikki Amuka-Bird, Dermot Crowley, and Michael Smiley, along with new faces Lucian Masamati and Ned Dennehy. The new episodes will be on our screens next year. Or, as it should be termed, Not Soon Enough.