Isla Fisher is releasing her first picture book

Isla took to Instagram to share a video of herself ripping open a package featuring the books.

She captioned the post: "I just received a very special delivery! Here's me opening the first copies of my brand-new picture book, Mazy the Movie Star illustrated by the incredible Paula Bowles!

"Mazy lives in Hollywoof and has her fur fluffed twice a day. While other dogs chase sticks at the park, Mazy chases her acting dreams. Then one morning Mazy's agent delivers bad news. Hollywoof has changed and there are no jobs for Mazy anymore. Can Mazy embrace what it is that makes her special and find her perfect role? #MazytheMovieStar #AmazingMazy #Hollywoof #ChildrensBooks #PictureBooks #DogsOfInstagram (sic)"

The book will be published in the UK on 29 September and the following week in Australia and New Zealand.

It may come as a surprise that the 'Wedding Crashers' star used Instagram to reveal her new book, as she previously branded the platform "toxic".

She said in February about the site: "It's toxic for children and the proliferation of fake news. They don't have to meet publishing standards, it appeals to our base instincts.

"Actually, I'm being gentle - Instagram increases bullying and fear of missing out and leads to anxiety and depression. So, obviously, I am no fan of Instagram."

Isla avoids posting personal items on her Instagram and uses it to promote her work, and she's previously admitted she is keen to keep her children's lives as private as possible.

She said: "Motherhood is actually my favourite topic - but I keep it private. I think all parents are trying to protect their kids, especially in the social media age.

"I want our children to have a normal childhood - being able to play outside without pressure or scrutiny. All kids have the right to just be kids, and I would never sell a film or magazine by speaking about (mine)."