Madame Doubtfire by Anne Fine
Lydia, Christopher and Natalie are used to domestic turmoil. Their parents' divorce has not made family life any easier in either home. The children bounce to and from their volatile mother, Miranda, and their out-of-work actor father, Daniel. Then Miranda advertises for a cleaning lady who will look mind the children after work - and Daniel gets the job, disguised as Madame Doubtfire. This bittersweet, touching and extremely funny book inspired the highly successful film Mrs Doubtfire, starring Robin Williams.