Dame Helen Mirren stunned crowds at the Cannes Film Festival by debuting a shock of bright blue hair.

The Oscar-winning actress, 77, arrived on the red carpet on the opening day of the 76th annual event on Tuesday.

Dame Helen wore her hair in a messy up-do highlighted with varying shades of blue and turquoise.

She paired the look with a floor-length periwinkle gown, which featured folds around the waistline and an elaborate bustle in the back.

The actress also carried with a black fan with #WorthIt written on it in a nod to her partnership with L’Oreal Paris.

She waved and blew kisses to fans as she posed for photographs.

Dame Helen’s eye-catching hair colour was not her first at the international film festival.

In 2019 she attended with a shorter cut that was swooped back and dyed pink.

She previously told US outlet People magazine that she had been inspired to make the changes after watching reality TV.

“I was watching an episode of America’s Next Top Model and there was this little English girl on it,” she said.

“She had bright pink hair and she looked so great.”