The movie recently received its world premiere at the New York Film Festival, and will later arrive in UK cinemas on November 7th.
Anemone also stars Sean Bean, who is seen in the trailer travelling out into the woods to come face-to-face with his estranged brother, played by Day-Lewis. The cast is rounded out by Samuel Bottomley, Safia Oakley-Green and Samantha Morton.
Anemone's synopsis reads: "Bonded by a mysterious, complicated past, the men share a fraught, if occasionally tender relationship -- one that was forever altered by shattering events decades earlier.
Ronan co-wrote Anemone with his father, and marks Day-Lewis' first movie since retiring from acting almost a decade ago.
Now, in a new conversation with Interview Magazine, Ronan has admitted that he was initially hesitant about the feature, but believed it was too much of a great opportunity to ignore, and a film that he would have lived to regret not making.
He shared, "Well, when we first started writing the film, we weren't even sure that it would turn into anything. Once we had 70 pages it felt like, 'This is actually going to be a feature script.' And then it was like, 'Oh, shit, what are the implications of us actually doing this?'"
Ronan continued, "I definitely had reservations at first, given the nepotism aspect of it. But I ended up feeling like, if I hadn't done this, in 10 years I would look back and think, 'How did you not take this opportunity to make something with your dad in this way?'"
Ultimately, he's thankful that he didn't let the nepotism tag prevent him from creating Anemone with his father, adding, "It was such a cosmically beautiful experience to be able to have together. I know how many people would kill to have this chance to make a film. I'm so insanely grateful."
In the same interview, Ronan described the creation of the movie as "serendipitous" due to both him and his father having an idea to make a movie, which centres around the theme of brotherhood. He expanded, "We just started bouncing ideas around about a man living in a state of self-banishment in the middle of the woods. That came to us without knowing why he was even in that state."
Last month, Day-Lewis shared his regret over publically retiring, admitting, "But looking back on it now -- I would have done well to just keep my mouth shut, for sure. [Laughs.] It just seems like such grandiose gibberish to talk about. I never intended to retire, really."