Cate Blanchett will play a villain in 'Thor: Ragnarok'.

Cate Blanchett

Cate Blanchett

The 46-year-old actress has joined the cast of the third installment of the Marvel movie franchise and while her exact role has not been confirmed, Cate's co-star Mark Ruffalo revealed she will be playing a baddie in the film.

Mark, 48, told Entertainment Tonight: "I saw her at the Governors' banquet and heard that maybe she was circling, they were talking to her about the part, so I ran up to her and I was like, 'Please, please, please make this work!'

"She's just one of the best, and to have her play a baddie is going to be really exciting."

Speaking to chat show host Jimmy Kimmel recently, Cate joked she was actually taking over the role of Thor from fellow Australian Chris Hemsworth.

She quipped: "Chris Hemsworth is busy, so I've been working out." When Jimmy asked: "Is that confirmation, or are you dodging the question?", Cate replied: "No, I'm not dodging the question! They're just substituting one Australian for another. Gender equality! Why can't you have a female Thor?"

Taika Waiti will direct the highly-anticipated film - which is expected to be in theatres in 2017 - whilst Stephany Folsom has recently finished the script.