Emily Blunt has revealed she used her “fragile state” during early pregnancy to help her take on her latest role.

The 33-year-old star discovered she was expecting her second child days before filming began on thriller The Girl On The Train, but used the hormone surge to get into the character of Rachel, an alcoholic who is struggling to accept that her ex-husband is remarried and now a father.

I think maybe my fragile state helped my fragile character, Blunt said.

I couldn’t tell anybody because I found out very early on – I think I found out right before I started shooting.

Her second daughter, Violet, was born in June this year, a sister for two-year-old Hazel.

The Devil Wears Prada actor told Sky News, although she has been able to have children herself, she drew on the experiences of friends for the part of Rachel.

I know a lot of people who have been unable to (have children) and what a traumatic experience that can be, she said.

I’ve seen it first-hand and understand it and feel for women who have had a hard time and really want it.

The Girl On The Train, based on the novel by Paula Hawkins, sees her character spying on two people during her daily commute, believing they are the perfect couple until she witnesses a shocking event.

I think to varying degrees everybody has those voyeuristic tendencies, wondering what happens behind closed doors, said Blunt.

I think we all are, subconsciously or consciously, interested in other people’s lives, especially a seemingly perfect life. I think that’s when people really want to know what goes on.

With regard to the media and fan interest in her own life, she said she doesn’t pay much attention.

The idea of other people wondering about my life sort of feels like white noise to me. I try not to think about it or buy into it too much.

The Girl On The Train is out in UK cinemas this weekend.

(c) Sky News 2016