"I’ve noticed I make noises when I get up and sit down now. I mean, my knees are rotten bad - I refused to wear knee pads too many times when I was doing stunts, and I just clobbered them up a bit. I am an old man in a young man’s body." Harry Potter star Daniel Radcliffe is suffering from 'old age' at 19. The young Brit turns 20 in July (09).