Who knew Cate Blanchett was so wicked? Finally, she's been exposed, and a good thing too.

If you've missed the weekend kerfuffle, we've learnt that Cate Blanchett is the wrong kind of rich — a person of means and profile prepared to stand up for causes more general than her own self-interest.

What was the woman thinking?

Blanchett's crime was lending her name to a cause she has long advocated: addressing climate change. Blanchett is appearing for free in television ads — launched last night — advocating Australia ''Say Yes'' to a carbon price.

The $1 million advertising campaign is driven by a coalition of green groups and unions, including the ACTU, WWF and Greenpeace.