Joel Madden ''didn't know'' what happiness was until he had a family of his own.

The 35-year-old rocker is blissfully content with his wife Nicole Richie and their two children, daughter Harlow, six, and son Sparrow, who turned five last week, and says their life together makes everything ''make sense''.

He said: ''I didn't know what happiness was until I had a wife and two kids. It never makes sense until you actually live it yourself.''

Joel is delighted his kids think he is the ''funniest guy on the planet'' and says nothing makes them happier than his regular ritual of serving them breakfast in the evenings.

He told the Sydney Morning Herald newspaper: ''Once a week, when I'm home, I do breakfast-for-dinner. And the kids love it.

''Maybe they'll get to an age where it's not funny any more but, at four and six, they think I'm the funniest guy on the planet.''

Joel is considering taking up boxing with his brother Benji again, though he admits he prefers the training to actual fighting.

He said: ''I just like the training. I like sparring, but I don't want to fight anyone.

''I've got a good mind. Especially since I've had kids, I don't need to hit anything or anyone. I don't have that spark that it really takes to fight anymore.

''But I like training with [Benji], and I like watching him fight. He's got a lot of spark.''