What began as something small, with no real ambition, grew until a full feature film and Day-Lewis’ long-awaited return to movies. Since 2017’s “Phantom Thread,” Day-Lewis has, among other things, studied violin making in Boston. At least, it wasn’t enough to stand in the way of him making a movie with his son. “I definitely was brought low after I finished shooting “Phantom Thread” more than for any other reason because I anticipated being back in the public arena again,” he says. (He also has an older son, Gabriel-Kane Day-Lewis, from his past relationship with Isabelle Adjani.)