"I just had a son and had to take him to the paediatrician and he measured his head and apparently he's in a group in which only 14 per cent of the population have a bigger head than him. Then she said: "Do you mind if I measure your head?" I said: "Go ahead." And she was shocked, because less than one per cent of the world's population has a bigger head than mine. So I guess that means I'm pretty full of myself. Or that I have a huge brain."