Cate Blanchett has the “ugliest haircut” she’s ever seen in the upcoming Indiana Jones movie.

The Australian actress says her “helmet” hair sends out a sign that she is playing a villain.

She told Britain’s Daily Mail newspaper: “I’ve got the ugliest hairstyle I’ve ever seen - a sort of pudding bowl helmet cut.

“If that doesn’t send signals that she’s the bad girl then there’s no point.”

Cate plays Spalko, a Soviet spy, in Indiana Jones and the Kingdom of the Crystal Skull and admits she loved the chance to be a baddie.

She revealed: “I actually found it quite liberating playing a really bad person.”

Cate’s co-star, Shia LaBeouf, heaped praise on the actress earlier this week.

He said: “I think that Cate is incredible. She might be the scariest villain in any of these films. She's terrifying.”

Cate also said she doesn’t plan on making any more movies for the time being as she is “happily enriched” with motherhood and the theatre company she runs in Sydney with husband Andrew Upson.

The couple have three children, Dashiel, six, Roman, three and four-week-old Ignatius.