What it was really like filming – and winning – BBC One's This Is My House

I found filming the show a joy. We had each been given a chance to see the house a few weeks before, at which point we also came up with a back story to our character: I was going to be a journalist working part-time at the Leicester Mercury, doing freelance pieces on the side in an attempt to break into journalism in London. As a freelance journalist, I didn't exactly need to ring Daniel Day-Lewis.

When we arrived at the house on the morning of filming, all four Mitches were kept in different rooms, like boxers before a fight. The first scene, in which we all meet, was excruciatingly awkward before it was edited and set to music. Like cats peeing, we were staking our claim on the house, so tended to say little other than “No no no, welcome to MY house.” I used a cafetière extremely badly. I remember wondering if we were the only quartet not to fire off zingers from the get-go.

People have asked whether I knew who the real Mitch was. Not to begin with. But in that initial scene, I was sure that I had guessed: I was confident that it was Mitch 4 (a lovely comedy performer called Phil Smith) because he so casually plugged a USB into the dining room TV. Off camera I told the director I knew. He said, “Yeah, it's quite obvious, isn't it.” We were talking about two different men.

For my first scene I went around the kitchen with Mitch 3 and Stacey Dooley and I confidently picked holes in his story. I thought that he was an actor doing badly and making up strange lies about “pasta for show” and “knives for show”; when he couldn't name his fish I thought it was because he hadn't managed to invent any names in time. Once the cameras stopped I asked him what his surname was. McCarthy-Kalischer, he said. After we'd done another scene and I popped upstairs, I noticed the name 'McCarthy-Kalischer' written on the globe in the study. I had been making fun of the real homeowner.

Sadly, a scene in which we all tried on the clothes of Mitch 3 and his husband Adam didn't make it. But I was glad that another scene did: a routine in which I talked through Mitch 3's wedding card collage with him. I was able to improvise stories about the various people who had written the cards – much more fun than trying to work the kitchen hob – and I could hear the crew laughing as I said, for example, that Mitch 3's uncle Alan (still alive) had passed away. Unfortunately, I don't think any of it was convincing. That's a feature of the show: real life is less interesting than fantasy, so to convince viewers you actually have to try to be more mundane than you would expect.

This is a fascinating question the show raises. More often than not, the episode's real homeowner has been the person who failed to give a smooth or rapid answer to a question. In our episode, the real Mitch couldn't remember what kind of diffuser was in his living room. This was evidence not that he was lying but that he was taking time to honestly remember the truth. If you're a performer you simply say the first thing that comes into your head because you don't know the truth anyway.

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When you play the game, you're seeing things through the eyes of the judges: how are they going to interpret your uncertainty? You try to have an answer for everything because if they see you stumble, they're actually quite likely to assume that you are an actor. We believe that people know the ins and outs of their lives. This Is My House proves that they don't. When someone says: “I don't know,” they tend to be the homeowner. Why should you know exactly which fragrance of diffuser you have in every part of your house?

I would love to see a second series because the performers watching the first would have picked up on all this, and will have been able to perfect their performances by making them imperfect. (A fun bonus would be using the house of an actor – four actors competing against each other.) As the show progresses, it should become fiendishly difficult to guess the truth. Even the real homeowner will wonder whose house it is.

The last episode of This is My House will air on BBC One on Thursday, 29th April at 9pm. All six episodes from series one will be available to stream on BBC iPlayer. To find out what else is on TV, check out our TV Guide or visit our hub for more Entertainment news.