The new episode due to be broadcast this December is titled The Devil Of Christmas, which stars Rula Lenska and Jessica Raine alongside Shearsmith and Pemberton. First revealed earlier this year at the Starburst Film Festival, the episode is set around an alpine chalet and involves the horned "half-goat, half-demon" Krampus character from Austro-Bavarian folklore. Set in 1978, it has been filmed by the production team using old 1970s filming equipment as a homage to the era.
It's a bit of playful 1970s comedy/horror with Rula Lenska in it. That's how you do it.
The other five episodes from Series 3 are then expected to be shown on BBC Two in early 2017. Settings include a restaurant after closing time and an art gallery. As previously reported, guest stars across the run will include Felicity Kendal, Jason Watkins, Keeley Hawes, Mathew Baynton, Philip Glenister, Sarah Hadland and Morgana Robinson.