Isla Fisher is releasing her first children's book 'Marge In Charge'.

The 41-year-old actress - who has daughters Olive, nine, and Elula, six, and two-year-old son Montgomery with her husband Sacha Baron Cohen - has announced her new venture, which will see her release three books in a series that will be published in America later this year.

The inside cover of the first tome reads: '''Don't worry about being perfect or you'll miss out on the fun!'

Explaining the synopsis to PEOPLE, she said: ''Jemima, who is the narrator and the eldest child, feels she has to be a 'good girl,' so thanks to Marge she learns to let her 'freak flag' fly and enjoy being a kid.''

Working on her literacy skills made the 'Keeping Up with the Joneses' star realise just how little youngsters are reading and how ''vocabularies are shrinking''.

She said: ''It saddens me when I think about how much vocabularies are shrinking - I know mine is, and there's only so much I can blame on lactation!''

When she was a little girl the flame-haired beauty used books as an escape from the real world and loved using her imagination when reading.

She explained: ''Stories were a fun part of my childhood. We moved around a lot as a kid (I was born in Oman to Scottish parents and moved to Australia when I was six), so I hid in books.

''Books take tiny people to places they can't go: on a pirate ship, inside a peach, through a looking glass

''They help children find quiet time, provoke thoughts and discussions and educate them. They are an integral part of childhood.''

Meanwhile, asked if she is like the lead character in her book, Marge, Isla said that becoming a mother-of-three made her mature ''overnight''.

She laughed: ''I wish I knew the answer to that. I love tapping into my inner idiot (and have made a career out of it), but having a family definitely turns you into a grownup overnight.''