The 47-year-old star appeared in one of the tents for an intimate reading of Blueberries For Sal by Robert McCloskey, reading the tale in a pair of white pyjamas.

She had come to the festival in Weston Park with her family.

The Titanic actress said she was a big fan of the event: "I've been to many countries, but my favourite country is England and my favourite festival is Camp Bestival."

The story, which first published in 1948, describes the adventures of a little girl and a baby bear while hunting for blueberries with their mothers one bright summer day.

Winslet said the book was one of her favourites as a child, and she read it to her children when they were young.

The Oscar-winner has three children, daughter Mia, 22, and sons Joe, 19, and Bear, nine.

Winslet was reading the book for CBeebies, following her first bedtime story for the pre-school channel at Christmas.

In her first appearance she read Grumpycorn by Sarah McIntyre, which is about a bad-tempered unicorn who learns how important teamwork is when he gets a bad case of writer's block.

Winslet's next film appearance will be in biographical movie Lee, in which she plays Elizabeth "Lee" Miller, a fashion model-turned-war correspondent for Vogue.

Lee will premiere at the Toronto International Film Festival (TIFF) this September.

Winslet recently won the leading actress award at the TV BAFTAs for her role in I Am Ruth, in which she starred opposite her real-life daughter, Mia Threapleton, and which also featured her eldest son, Joe Anders.