PhoneShop star Tom Bennett plays Pete in Family Tree...

Hi Tom. Can you describe your character and his relationship to Tom?

I play Pete Stupples, who has been Tom Chadwick's best mate since they were five. Then, around the age of 11 or 12, Tom went off to Ireland to live with his mum, hence his accent. When he comes back it's like nothing has changed between them and they are still the same best mates.

Where is the character of Pete in Tom's life when the series begins? How does it change as Tom's quest to discover his family history begins?

Chris O'Dowd's character Tom is left a box of antiques, bric a brac and family 'heirlooms' by an old dead aunt. As he starts to go through them, he asks his dad questions about his ancestors based on what he finds in the box beginning with a photo, seemingly of his great grandfather Harry Chadwick. His dad doesn't know a lot so Tom starts to research his family tree.
On these journeys he finds various little characters, and me, being his best mate and up for a laugh, not the sharpest tool in the box, but up for a road trip, I go with him and I get into bits of trouble along the way. Pete does keep his spirits up throughout his journey though.

Christopher Guest works in a unique style of improvised filmmaking. Do you enjoy the challenge of working this way?

Chris Guest is the godfather of improvisational comedy. It was such an honour to be on set with him, to witness the process and to be part of it. For him to think that I'm good enough to be doing what he wants me to do is quite an honour.

How did he work out that you were good enough?

The first meeting we had was just me and him in a room, just two guys having a chat. I came out of that meeting not knowing how it went. Usually when you do an audition you come out and think you've either ballsed it up or done okay, but with this one I had no idea. Then I got the call a couple of months later saying they wanted to meet me for Pete, which was amazing.

Did it help you to have a character description to work from and how did that help you in your creative process of coming up with how you are going to play him?

The Christopher Guest process is unlike anything I've done before. The breakdown of my character Pete included the purpose he serves to the story, his character traits, information on what schools he went to and how long Pete and Tom have been friends for. Then you get a plot breakdown of what happens in each episode, turn up to set and someone shouts ACTION. No pressure.

How long did it take before you found yourself at ease with the process?

I have the sort of temperament where I try not to overthink things, I don't get flustered and I don't panic. I'm not overly neurotic. I'm quite zen about the whole thing. You just have to trust in the fact that Christopher Guest has picked you to do this job so he believes you are the right man for it. The fact that he thinks I'm the right man gives me a certain amount of confidence. It's just a case of not overthinking everything, not panicking, trusting in your own limited abilities and getting on with it really.

He obviously trusted you enough to choose your own wardrobe?

I had great fun picking the wardrobe and that's another thing about Christopher - he trusts me enough to make the character my own and work with it and make the funny things happen and so he also trusts me enough to know what wardrobe my character would wear. I had a great eight hours in town spending lots of money on terrible clothes. I don't wear skinny jeans but Pete would and he would wear silly hats, so I had great fun picking them.

Pete and Tom have known each since they were kids but you hadn't worked with Chris O'Dowd before. How did you conjure up this lifelong friendship out of thin air?

Christopher and Jim Piddock have written Tom and Pete so that there is a natural interplay between them. They fit together, as long as you have worked out who your character is, which we had. Then Chris O'Dowd and I have to trust that we are both capable of being "best friends".

Then add to that the chemistry of improvisation, which is a really personal element as well. Then there are a lot of things you are trusting will fall into place. But I think that is one of Christopher Guest's many talents - having a sixth sense and saying "yes I can see that, I can see those two working and I can see them having the right levels of chemistry and really playing with it". It's not about being afraid to play and not being scared of making mistakes. If you completely balls it up then we can go again, but you want to be free enough and at ease enough to have fun and not worry about it. I think Chris O'Dowd and I found that place where we both felt comfortable with that.

Pete seems to be up for anything. Why do you think he follows Tom on this journey of self-discovery?

Pete is a slightly simple person who just wants to have fun and thinks that everything is a laugh. So this is perfect for his sense of adventure. The fact that Tom is now going on a journey which essentially, in Pete's mind, is one big rude road trip is just fun for him. He's a simple soul and he's easily pleased so this is great. He's going to places he's never even heard of. He thought Hove was up north before he went there and discovers it's on the coast, which is great! And he gets to wear the front end of a pantomime horse. These are good things, things that Pete enjoys.

Is ancestry something that has interested you in your own life? If so, do you have any specific stories that came out of looking into your family?

My dad has done a bit of research on our family tree and we can trace it quite far back. My dad believes he has traced us back to being a great-great-great-great-great-great cousin of Wellington. Whether that's true or not, I've yet to see the piece of paper, but he believes that's true and I don't disbelieve him because my family has lived in London for generations.

Also, there's a really good story that my dad's great grandmother who owned a pub in Whitechapel was getting people out one night, looked down the road and saw a tall man in a cape and a top hat washing blood off his hands in a horse trough. So there's an urban family myth that my great-great grandmother saw Jack the Ripper!

Can you tell us about your favourite Christopher Guest movies and moments?

It's actually too easy to just say 'all of This Is Spinal Tap'. There are the bits that we know and love - the miniature Stonehenge, "It goes up to eleven" - there are just too many to mention. I've seen every Christopher Guest film he's made and I'd seen them all before I knew I was working with him. In A Mighty Wind, Fred Willard explaining who he is and where he's come from is ridiculously funny. Chris Guest freeform body popping in Waiting for Guffman...

What is really scary is how good his crew are - Eugene Levy, Harry Shearer, Jennifer Coolidge, Fred Willard, Jane Lynch, Catherine O'Hara, Parker Posey. These people are ridiculously good and that's intimidating, extremely intimidating.

This show is aiming to be a very funny comedy, but it also aims to have a lot of heart - how important is that to you?

I think any decent comedy worth its salt has to have heart otherwise it's just a bunch of jokes. I think people enjoy comedies that have a heart and soul to them. So it's Tom's journey to discover where he came from, who his family were and also who he is now, because in discovering his family and family tree he takes steps towards discovering who he is as a man. Pete's journey is probably not quite the same but then he is a simple man with simple pleasures and as I've said, he's just up for the craic.