PICTURE the scene: an eclectic group gathers in a remote lodge in the Highlands, their contrasting personalities a brewing cauldron of trouble, one that is fizzing with thinly veiled put-downs, simmering rivalries and fragile bonds pushed to the brink.

It could be the plot of an Agatha Christie novel or, in this case, the perfect setting for a Christmas special of BBC Scotland comedy series Two Doors Down.

The brand-new episode sees the gang swap Latimer Crescent for a luxury escape as Colin and Cathy, played by Jonathan Watson and Doon Mackichan, find their plans for a Christmas getaway in Dubai thwarted by the coronavirus pandemic.

Instead, they rent a plush lodge and invite their friends and neighbours Beth, Eric, Christine, Ian and Gordon – Arabella Weir, Alex Norton, Elaine C Smith, Jamie Quinn and Kieran Hodgson – along to liven up that dull bit in-between Christmas and New Year. What could possibly go wrong?

Here, Watson and Mackichan share their own festive traditions, faux pas and reveal which of the Two Doors Down characters they would have round the table for Christmas dinner.

Did you have fun filming the Christmas special?

Doon Mackichan: It was even more fun than usual because we were all so grateful to be together after such a long time. From not knowing if the Christmas special was going to happen at all, it suddenly happened and was all very last minute which was wonderful.

Then there was the fear of "how will we do this?" and whether it would be strange with everyone in masks and socially distanced. But it was so well done. The protocol was strict and we all felt safe. It was wonderful to be together again.

Jonathan Watson: It is always fun filming this job. You are working with good actors and good scripts. We always have a good time – this was no exception. With everything that has happened this year, I'm just glad to be working. I'm in a fortunate and privileged position.

The camaraderie is great. We isolated together for the length of the shoot. We have known each other a long time now – and some of us have known each other for a very long time. There is a shorthand we have built up and that makes things easier.

What were your standout moments?

Mackichan: When we got to the hotel, we all had to have Covid-19 tests and isolate for two days. Then, we all came out of our hotel rooms and were in the corridor and that was us officially in a bubble. We all had a glass of Champagne down the hotel corridor. That was joyful.

On set, it was lovely to be in the Scottish countryside and not be in a tiny shed in Dumbarton. We had a sense of space and light and it was amazing with the weather, where one minute there was a rainbow, the next minute it was hail and then the sun was shining.

HeraldScotland: Doon Mackichan and Jonathan Watson in the Two Doors Down Christmas special. Picture: Alan Peebles/BBCDoon Mackichan and Jonathan Watson in the Two Doors Down Christmas special. Picture: Alan Peebles/BBC

The poor cameramen had a right old job because of the windows – it was like being in a glass box. It was great being able to see and stand outside because all the doors were open. It was quite cold, but it felt safe.

Watson: Wrapping on schedule. Because of all the different restrictions you have to adhere to, it was a real achievement finishing it on time.

Which of the Two Doors Down characters would you invite for Christmas dinner?

Mackichan: I would have the whole gang because of the ridiculous conversation. You couldn't not have Christine, Cathy, Gordon and Ian. I would tape it and write an episode.

Watson: None. They wouldn't be getting anywhere near the Watson household. Well, maybe Beth and Eric at a push.

Who would be your dream guest?

Mackichan: Queen Boudicca. She would rock up with her daughters, park her chariot outside, get all the neighbours talking. She would be able to speak about being a feisty woman in these mad times and how to keep going. Queen Boudicca would be an inspiring person to have come for Christmas dinner. She would be a good kick up the a***.

READ MORE: 10 great Scottish festive books, films, TV shows and songs

Watson: I could reel off a long list, but I think Christopher Walken might be a bit of fun. He would be interesting and keep things ticking along nicely.

Do you have any Christmas traditions?

Mackichan: We all go to my brother's house and do a lot of singing round the piano. A lot of close harmony singing and reggae Christmas carols. We have a very late lunch and a big walk in a place called the Firehills which is a country park in Hastings.

Subject to the tier restrictions we will be gathering at my brother's, but we don't know how many of us will be allowed to this time.

Sadly, I won't have my son and daughter here. My daughter, who is 25, is in Thailand teaching and my 24-year-old son is in Manchester. I will be with my 16-year-old daughter. It will be sad not to have all the kids, but we will make the best of it.

Watson: The three of us – me, my wife and son – get together for Christmas Eve. We have a meal and watch a Christmas film. We have done that for years (my son is 21 now) and I think we will do it again this year. On Christmas morning, we get up and open the presents around the tree.

HeraldScotland: Doon Mackichan and Kieran Hodgson in the Two Doors Down Christmas special. Picture: Alan Peebles/BBCDoon Mackichan and Kieran Hodgson in the Two Doors Down Christmas special. Picture: Alan Peebles/BBC

The nearest we have come to matching pyjamas is when my wife got me and my son matching Elf T-shirts. Elf is one of two Christmas films we watch. We either watch Elf or Sleepless in Seattle on Christmas Eve. I love Christmas Eve. It is my wife's favourite day of the year.

Best childhood present from Santa?

Mackichan: Caran d'Ache felt-tip pens. I was probably about nine. They came in a big, long tin and were the most impossibly beautiful colours. I couldn't believe these colours existed. I then drew princesses for about two years. I loved these pens.

I still draw and do a bit of painting. I think that got me going because I now do watercolours of flowers and things. That explosion of colour was such a great thing to give a child.

Watson: Scalextric. In fact, it was only recently I got rid of it. I was eight or nine when I got it for Christmas. It was Scalextric 500, where you could have a figure of eight where it goes up and over, or you could make it into a wide-ranging oval.

Biggest disappointment on Christmas Day?

Mackichan: I used to be quite annoyed at the satsuma – I never quite knew why that was. The smell of it always makes me think of Christmas so actually it was probably a good gift.

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I was speaking to a friend who had been in prison at Christmas once and they literally got a tangerine in a brown paper bag thrown through that little thing [the hatch in the door] with one of the screws going: "Merry Christmas".

Watson: I can't think of any.

All-time favourite Christmas moment?

Mackichan: On Christmas Day, when we lived in Scotland, we used to walk from Upper Largo, Fife, to Elie along the chain walk.

I remember we would slide down steep grass hills on bags. You could also do it on the back of a coat. It was like grass-boarding but on a coat or thick plastic sack. You had to be careful about stones, so someone would clear a path and once you had been down it a few times, you would bomb down.

HeraldScotland: Jonathan Watson, Doon Mackichan, Elaine C Smith, Arabella Weir and Alex Norton in the Two Doors Down Christmas special. Picture: Alan Peebles/BBCJonathan Watson, Doon Mackichan, Elaine C Smith, Arabella Weir and Alex Norton in the Two Doors Down Christmas special. Picture: Alan Peebles/BBC

When we got to Elie, we would have a wee glass in The Ship Inn, then go back home for our Christmas dinner. If it had been snowing – the best thing ever – we would do moonlight sledging.

Watson: Going into the room on Christmas morning and seeing all the presents laid out. When I was wee boy, I was always led in with my eyes shut.

We did that when my son was younger too. You open your eyes and see all the presents waiting for you. I have a lot of great videos from Christmas morning with our son, capturing his initial reaction when he saw them.

Any festive faux pas?

Mackichan: Drinking port when I was too young and feeling sick all night. I think that must have been early rehearsal for Cathy. I took a sneaky sip. I wanted to taste what it was. Then drank the whole thing. I felt bad but couldn't really say why to my parents. I was about seven.

READ MORE: Our guide to the 50 best books to give this Christmas

Watson: A long time ago – we're talking 30-odd years – I remember getting my mum a Hoover. She didn't want to seem ungrateful, but I went out to the Boxing Day sales and got something else to replace it because I could see it just didn't quite get the reaction that I thought it might.

What are you asking Santa for this year?

Mackichan: The end of Covid. It has been great for people finding nature, empathy and helping those around us. That has been a thumb's up, but in terms of our profession it has been terrible and likewise for mental health.

Watson: My wife says I'm impossible to buy for. My son is good at picking things, so he will be a major influence. I don't know what I will get. I have no idea and that is part of the fun.

I only have my wife and son to buy for. I enjoy Christmas shopping and always try to get something that is useful, pampering and that they don't expect but I know they will like.

HeraldScotland: Jonathan Watson in the Two Doors Down Christmas special. Picture: Alan Peebles/BBCJonathan Watson in the Two Doors Down Christmas special. Picture: Alan Peebles/BBC

Who would you love to have around the dinner table this Christmas?

Mackichan: I would like to have all my kids in one room. I haven't seen them since February. I would like to have my dad, Rocky, who is no longer with us, back at the table. Friends and family are all you can ask for. I feel very grateful I have my brother, sister, mum and younger daughter with me.

I am very blessed to have family. We will be inviting people who don't have family as well. It is a time to take care of the older generation and make sure they are not alone.

Watson: I'm grateful the three of us – me, my wife and son – will be together this Christmas.

What will you be doing on Christmas Day?

Mackichan: Going to my brother's house if we are allowed. We miss gathering and singing, so we need to sing round the piano – socially distanced with all the doors open.

READ MORE: Val McDermid on her 'odd' festive traditions and why she loves a Christmas murder mystery

Watson: I'll do the turkey; my wife does all the veg and the puddings. For Christmas Day, she makes a trifle that is tremendous.

The starter is usually smoked salmon and brown bread. Turkey with chestnut stuffing, chipolata sausages wrapped in bacon, roast potatoes in goose fat. Then the trifle. I'm hungry thinking about it.

What is your favourite Christmas food?

Mackichan: Cranberry sauce, gravy, sprouts – when the plate is swimming in weird flavours you only have once a year. I love that.

Watson: The trifle. My son and I could each eat an entire bowl to ourselves.

Do you have any Christmas TV traditions or favourite festive movies?

Mackichan: It's A Wonderful Life. That is one we watch and have a little blub, being a bunch of sentimental old fools. I don't tend to watch anything on Christmas Day and then maybe just stare at something on Boxing Day. I'm not a great telly watcher. I prefer to read.

HeraldScotland: Jonathan Watson and Doon Mackichan in the Two Doors Down Christmas special. Picture: Alan Peebles/BBCJonathan Watson and Doon Mackichan in the Two Doors Down Christmas special. Picture: Alan Peebles/BBC

Watson: My son will watch Doctor Who if it's on. I tend not to watch TV and usually potter with my presents. We watch Elf and Sleepless in Seattle on Christmas Eve. I enjoy old films like It's A Wonderful Life and White Christmas because those are the ones I remember from when I was a wee boy.

Will you be watching the Two Doors Down Christmas special?

Mackichan: If they [her family] don't all gather in front of the TV, there will be hell to pay. I have done that a few times in my life: "Mummy's on TV!" and there is no response.

My mum will certainly watch it and if we can all be in the same place that would be lovely. I haven't got a very big TV, so probably at my brother's where there is a bigger telly. That said, I do find a group watch hideous. I hover at the door with my hands over my eyes.

I'm looking forward to seeing the Christmas special because it was such fun to shoot. What we managed to do in five days … it was a lot to get through. There was a lot of focus and energy on set – and a lot of coffee.

READ MORE: Festive comfort and joy: What to eat and drink this Christmas

Apparently, I made the strongest coffee in the whole world and no one had ever drunk it that strong. They were buzzing. That kept us going. It was pretty full on. Being Cathy for 12 hours, holding a cigarette and a drink, I had quite bad shoulder pain after that – I needed a massage.

Watson: I'm not a great one for watching myself on telly to be honest. We might do. I tend to watch from behind the couch.

The Two Doors Down Christmas special will air on BBC Two, December 28, at 9pm, with a repeat on BBC Scotland, New Year’s Day, at 9.30pm​