Olivia Colman looks completely different with dramatic hair transformation in Only Murders in the Building

We're counting down the days until Only Murders in the Building returns to our screens with its hotly anticipated sixth season. 

Steve Martin, Martin Short and Selena Gomez reprise their roles as the beloved crime-solving trio, Charles, Oliver and Mabel, as they jet off to London for their latest case. 

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The new season welcomes an impressive cast of British stars, including Olivia Colman – who looks almost unrecognisable in a behind-the-scenes clip, trading in her signature brunette pixie cut for long, grey locks. 

In the clip, shared on the show's official Instagram account earlier this month, series regulars Meryl Streep, Martin Short and Selena Gomez introduce the Broadchurch actress as the latest guest star. 

While details about Olivia's role have been kept firmly under wraps so far, her character wears a long, period-style brown dress with a pinned-up hairdo. 

As the countdown to season six begins, here's all we know...

What is Only Murders in the Building about?

The Emmy-winning series follows three eccentric neighbours, Charles, Oliver and Mabel, with a shared interest in true crime podcasts, who begin investigating a string of murders in their upscale Manhattan apartment, producing their own podcast along the way. 

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What happens in season 6? 

Season six sees Charles, Oliver and Mabel take on their hardest case yet when the next victim - Cinda Canning - arrives at their doorstep, summoning them to London to catch her killer. 

The synopsis continues: "Our beloved trio of true crime-solving podcasters must now navigate their way through the home of the cozy murder mystery, replete with a whole new collection of suspicious and particularly English-eccentric characters. 

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"But can they follow in the footsteps of the woman whose podcast started it all for them… without having their story end the same as hers?"

Who stars in Only Murders in the Building season 6?

Meryl Streep returns as Loretta Durkin, alongside the core trio Steve Martin, Martin Short, Selena Gomez. 

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The series welcomes a stacked cast of guest stars for season six, including Tina Fey, Meryl Streep, David Tennant, Nicola Coughlan, Martin Freeman, and, of course, Olivia Colman. 

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Geri Halliwell-Horner, Jamie Demetriou, Anjana Vasan, Jane Horrocks, Derek Jacobi and Lesley Nicol have also joined the cast. 

When will Only Murders in the Building be released? 

Season six premieres on 8 December on Disney+.