The Gus Van Sant-directed drama, which was booed by some critics at Cannes Film Festival in France last week (15May15), features a widowed man, played by MCConaughey, who travels to Japan's famous Suicide Forest to take his own life.

The movie features flashbacks of his complicated relationship with his late wife, portrayed by Watts, and in an effort to connect with each other, the actors decided to bring back the old-fashioned practice of penning handwritten letters to each other.

In a press conference during the annual French festival, Watts told reporters, "Matthew reached out to me via e-mail and this idea just came to me. Having heard that Matthew works very much from an internal place, I said, 'Do you mind if we write to each other in character?' Because sometimes writing can be much easier than talking on the phone. If you can't get in a room with a person and see their eyes and take time with a conversation, writing can be a good way to connect."

Watts revealed the Oscar winner responded within 10 minutes with a simple response that read, "Write at will. Love, Arthur."

The actress added, "I just felt that was a fantastic way for us to move into this project and create that history... Sometimes the e-mails consisted of a few words and sometimes they were three pages long. Sometimes they would be argumentative. Sometimes they were poetic. We would talk about how things had gone wrong in the marriage in the voices of Arthur and (her character) Joan. So by the time we got to the set, we had a good month and a half of these letters."