Nicole Kidman and her sister used to speak to each other in a secret
language.

Nicole Kidman shares secret language with her sister

The Oscar-winning actress is very close to sibling Antonia and says they
spoke in a hidden tongue when they were growing up.
Nicole - who is godmother to two of Antonia's four children - said: "We used
to have a secret language and all sorts of stuff. No-one will ever come
between us. We need that love and support from each other, and we're both
willing to give it. She's grown up all her life with a sister who's an
actress, and she's been a part of it and held me in her arms when I've
cried. She's seen the failures and the successes, and I've seen hers."