Help me to find the book!!

There one scene i remember. She ask her friend (name sophia i believe) to pretend to her daughter's mother so that the H doesnt think the little girl belong to her and him. The little girl get along because her mother told to play game and call her auntie. H feel a bond between them, keep playing with little girl. Sometime little girl almost call her 'mother' instead of 'auntie'. I remember the author put character of her is miranda kerr.. pls help me to find this