As he chats away, it seems DiCaprio has come a long way from the ill-at-ease, reticent young man he used to be. He puts some of that down to the huge influence his mother, Irmelin, a German immigrant who arrived in America after the Second World War, still plays in his life. 'I can only hope to find a woman who possesses half the qualities of my mother,' he says quietly. 'She is one of the most hard-working, loving people I've ever met.