Daniel Day-Lewis doesn't ''understand'' his own decision to quit acting.

The 60-year-old actor announced last year that he would be retiring after 40 years in the industry, and he is now looking forward to ''exploring the world'' differently.

Speaking during a screening for his final film 'Phantom Thread' at the Stavros Niarchos Foundation Centre in Athens, Greece, he said: ''I don't fully understand it, but it came to me with a sense of conviction and so I chose to move forward in acceptance of that rather than struggling with it. [Acting] saved me from myself when I was a kid. But I just feel it's time to explore the world in a different way.''

Daniel previously admitted he no longer ''believes in the value'' of acting.

He said: ''I need to believe in the value of what I'm doing. The work can seem vital. Irresistible, even. And if an audience believes it, that should be good enough for me. But, lately, it isn't. I've been interested in acting since I was 12 years old, and back then, everything other than the theatre - that box of light - was cast in shadow. When I began, it was a question of salvation. Now, I want to explore the world in a different way ... I knew it was uncharacteristic to put out a statement But I did want to draw a line. I didn't want to get sucked back into another project. All my life, I've mouthed off about how I should stop acting, and I don't know why it was different this time, but the impulse to quit took root in me, and that became a compulsion. It was something I had to do.''