Simon Pegg says fans assume he's always happy simply because he's a comedian.

Speaking at the London premiere of 'Hector and the Search for Happiness', in Leicester Square, Pegg reflected on what makes him happy, which is the central theme of the new comedy drama.

The 44-year-old said: ''I think people assume if you're an actor and work in Hollywood you must be happy. That's not always the case, but I've found my happiness in Hertfordshire, north of London.''

The flick sees Pegg play the role of Hector, a psychiatrist who sets out across the world to discover what makes people happy, and the 'Star Trek' actor revealed what makes him content.

He said: ''I haven't been on a journey like Hector but I went on my own journey personally. As you grow up and live life you start to figure out what happiness is to you.

''It took having a kid and finding out what I want from life. It's an important thing we've all got to strive to find ... and also to realise sometimes that when you're unhappy it might be a prelude to being happy again, it doesn't mean you never will be again.''