Emily Blunt quickly learned Hollywood wasn't made of ''rainbows and sunbeams'' when she joined the industry.

The 'Girl on the Train' star had a particular expectation of the film industry before she got involved in it and she admits it is far from what she ever thought it would be.

She explained: ''It is a business that you enter into, especially as I did, and it appears to be made of rainbows and sunbeams. Then you realise it's called show business because it is a business ... I am not cynical in my personal life. I actually feel quite hopeful. But with the business itself, you have to approach it in a harder way. I think you have to wear a helmet.''

Asked how she realised Hollywood was like this, she added: ''It was just an accumulation over the years ... You are part of a machine that is moving and will overwhelm you and drown you if you are not tough in it. It's a very precarious industry that can often be quite crushing, so any advice I have for anyone going into it is to do something else.''

Emily got her first real break at 18-years-old, when she played the granddaughter of Judi Dench's character in West End show 'The Royal Family'.

Speaking about Emily, Judi added to Vanity Fair magazine: ''Poor Emily. It wasn't a great play, but we had the most fun doing it. I think she was quite young and frightened and insecure when we did The Royal Family ... You kind of know with somebody's attitude. She has a great sense of humour - which is more important than anything - a huge talent, and was ravishingly pretty.

''My grandson was about six, and he fell for Emily in such a big way. Now whenever we see Emily - he is 20 now - he jokes, 'She'd never have gotten where she was if I hadn't kissed her.' It doesn't surprise me at all where she is. I am thrilled that she is a big beautiful star.''