Hugh Laurie doesn't know what fun is.

The 51-year-old British actor insists he has no idea why he always feels unhappy, despite having three children with wife Jo and huge success in US drama series 'House'.

He said: "I'm not a naturally cheerful person. I don't know why that is. I've tried all sorts of remedies, like vodka - which works but not for very long.

"People say, 'Have fun!' Fun? I don't know what that is. For most of my life I've had people telling me to cheer up. It must be something about my face. It's just the way I am."

Hugh resides in Los Angeles' lavish Four Seasons Hotel while filming 'House' but insists he rarely takes part in typical activities of the city when he isn't filming.

He added: "My life in LA is just work. I don't surf, I don't rollerblade, I don't do yoga - I just go to work."