Meryl Streep ''terrified'' the screenwriter of 'The Devil Wears Prada' with her portrayal of Miranda Priestly.

The movie recently celebrated its 10th anniversary and Aline Brosh McKenna says the Oscar-winner actress was so convincing in her role as the fierce fashion magazine boss, that she scared everyone when they first saw her in character.

Aline said: ''She was terrifying. The first scene I saw was when she turns around to glare at Andy from the top of the stairs. I was so terrified by her look alone that I threw my arm out in front of the director like we were in a car wreck. I was so scared.''

At the start of filming, Meryl, 67, sat down with Aline, director David Frankel and producer Wendy Finerman so they could make Miranda as convincing as possible.

Aline told Vanity Fair: ''We sat with her for a long time, maybe four or five hours, and went through it. I don't think I'll be surprising anyone when I say she was incredibly smart about the script and incredibly smart about the character. She really stressed the lack of vanity about Miranda - that Miranda was really focused on her work and was under certain pressures, as a woman in that position of power. I do think a lot of female bosses struggle with people thinking they're a bitch, or they're cold, or they're difficult.''

The film - which also starred Anne Hathaway and Emily Blunt - was based on the bestselling novel from Lauren Weisberger.