Family Tree: Characters that aren't so everyday

A lot of people have asked me what my role in Family Tree was. Actually, only one person has asked me and that was my wife.

Basically, I co-wrote, directed, and executive produced Family Tree. I also co-wrote the song at the end of the show.

I have always been interested in genealogy, and after my dad died I began looking into my family history. He left me many boxes filled with photographs, diaries, war medals, and his toy soldiers.

I met with Jim Piddock, my co-writer, and we began to lay out a story. We created a fictional family and their entire family tree going back many generations.

It was a real joy working with Jim and it felt as though we had been writing partners for a very long time.

We spent many months coming up with the names of characters and trying to figure out their back stories, such as where they went to school, and what kind of music they liked.

There are many scenes in the show that stand out as favourites.

The dates Chris O'Dowd goes out on, Nina Conti performing her ventriloquist act at a Greek wedding, and Tom Bennett (Chris O'Dowd's best friend) working at a children's zoo.

The main character in the show is Tom Chadwick played by Chris O'Dowd. I first met Chris in London over a year ago and realised instantly that he would be perfect for the role.

I was searching for an actor who was funny, endearing, and who could improvise. Chris was able to do all those things brilliantly. A very rare thing.

The method I use as a filmmaker, shooting without a script but rather having a series of outlines, was used in the making of Family Tree.

I discuss the scenes in great detail with the actors but there is actually no rehearsal. I've often compared it to musicians improvising together.

The actors must listen to one another very closely and know when to solo, if at all.

I always knew Nina Conti would be involved. Or hoped she would. The part of Bea was created for her.

Nina appeared in For Your Consideration, a film I directed, and she was fantastic. It's amazing to behold her talents as a ventriloquist and as an actress as well.

Jim Piddock and I wanted to populate the show with eccentric characters. We read somewhere that creating dull characters wasn't as good an idea.

Characters come from years of observing everyday people. Apparently they aren't so everyday after all.

It's difficult to pick one character that I am most fond of. I think they all work well together.

Christopher Guest directed, co-created and co-wrote Family Tree. He is also is one of the executive producers for the series.

Family Tree continues on Tuesdays on BBC Two and BBC Two HD at 9pm and BBC Two NI at 11.20pm. For further programme times, please see the episode guide.

Comments made by writers on the BBC TV blog are their own opinions and not necessarily those of the BBC.