Karl Pilkington plays Dougie, the caretaker and flatmate to Derek in the Ricky Gervais comedy...

Hi Karl. How did Ricky recruit you to play the role of Dougie?

We were out having something to eat and he said to me, "I'm doing this new series called Derek. Do you fancy being in it?" He's always saying that - he got me to do a couple of lines in Extras. I replied, "It's nice of you to ask, but you know I'm not an actor. Why don't you get someone who knows how to do it?" I felt guilty about the idea of taking the job from a proper actor. But Ricky persisted, telling me, "All you have got to do is be yourself". I thought, "I can do that!"

Please outline your character for us...

Dougie is me if I hadn't had any luck. Although he hasn't been very lucky, he always tries his best. Deep down he still knows that life is basically rubbish, but we can't do anything about it.

How does he regard his job at the nursing home?

As much as he moans about his job, part of him likes it. It gives him a sense of worth. Like a lot of people, the highlight of his week is Friday when he gets paid. But despite his complaints, Dougie knows he has to keep working. In fact, he thinks that everyone should work. He hates scroungers and people who come to the nursing home hoping to benefit from their relatives' wills. He's always complaining about Britain's Got Talent and people who don't want to work for a living and just look for an easy life.

How did people react to the pilot of Derek?

My dad is a pretty good critic - he is not afraid to tell me if he thinks something I'm in is bad. But he really liked the pilot. The show messes with your emotions - it makes you laugh and cry - and there is not much around like that.

What is your take on Ricky as a director?

He's incredible. It's amazing how he knows exactly what he wants in every scene. He is able to explain what you're doing wrong, and you just get on with it. It's over before you realise you've done it. It never gets to the point of him screaming and shouting. When he says to me at the end of a scene, "That's all right", I think, "I got away with it again!"

What do you think of Ricky as an actor?

Ricky is a brilliant actor. I find it odd watching him act because I know him so well. Even though I know what is coming in every scene, he still does things that leave me with a lump in my throat. I know it's only acting, but it still gets a great reaction. Whenever he does that, I always think, "I can't do that. I'm going to get found out here!"

Do you think Derek can help change society's view of older people?

It's a nice thought that after watching this viewers might be more pleasant to old people all of a sudden. It's probably not going to happen. But if this show makes one or two people change their view of older people, that wouldn't be at all bad.

Does this mean a new career for you as an actor?

No. This is not a new line of work from me. I'm not looking to become an actor. I still don't feel like a proper actor. Kerry is a proper actress. When you're doing a scene with her, you're looking over your shoulder and thinking, "Blimey, she's really good". The hardest part is remembering the lines and trying not to laugh. Ricky is determined to make me laugh all the time - that must drive the crew mad!

Have you got a lot out of this job?

Yes. I've learnt a lot, and it's been a great experience. Ricky has been great. From the start, he's told me, "You can do it. What are you worried about?" I suppose I can't believe my luck. I've got no qualifications, but I've been given this great opportunity and I want to make the most of it. I suppose Ricky didn't go to drama school, either. In the end, if you can convincingly be that person onscreen, what does it matter?

Finally, have you enjoyed working on Derek?

Yes. I'm a bit rubbish at knowing when something is good. But if it goes out and I can say, "I wasn't as bad as I thought I would be", then I'll be happy. Until then, I'll be thinking, "I shouldn't be here!"

Derek is on Channel 4 on Wednesdays at 10pm from 30th January 2013. Episode Guide