ACTRESS Emma Thompson has criticised the "terrible" pressure facing young actresses to look like they are models.

The Nanny McPhee and Sense And Sensibility star said actresses in their 20s who were looking to reinvent themselves were often told "you've got to be thinner".

Thompson, whose mother is the Scottish actress Phyllida Law, raised concerns about the impact of social networking websites, where children are "reviewed every day" by posting on the sites.

"It seems young actresses are under pressure to look a particular way," said. Thompson, 54.

"If they get on to the red carpet they're all having to walk like models and dress like models. I think the pressure is terrible."