Sir Kenneth Branagh "embraced" the chance to return to his childhood in 'Belfast'.

The 61-year-old star has written and directed the new autobiographical movie and described his family's decision to leave his native Northern Ireland to escape the Troubles as the "defining" moment of his life.

Kenneth told the I newspaper: "It was a defining moment in my life, and it became clear to me, that was the last point at which I happily knew who I was. Since then it feels as though a series of masks and disguises have been worn.

"In a way, the writing of 'Belfast' and the making of it was really just taking off these masks and saying: 'You may think of me as a Shakespearean actor or a bumptious over-achiever' – if you think about me at all, but for what it's worth, I happily embrace the fact that this is a defining part of who I am, and that finding that way to go back home again was important."

Kenneth admits that he felt it was "necessary" to revisit his childhood in the movie – which stars Dame Judi Dench and Jamie Dornan – as his family have been reluctant to talk about it.

The 'Murder on the Orient Express' filmmaker said: "I didn't set out for it to be sort of public therapy, but I felt that it was necessary to write. Nobody in the family had spoken about these difficult times, even though I wrote about it then. Family never spoke about what riots were like or, the wrench of leaving.

"They believed you had to own the decision and not look back. Indulging in your personal sorrows was not something they thought was right and proper."