The Giver is based on a popular Young Adult book by Lois Lowry. It's set in a futuristic world where a magical figure known as the Chief Elder (Meryl's character) assigns every child a job they'll have to take on as adults. The main character is a boy who gets the job of holding all the world's memories.
The boy will be played by Australian actor Brenton Thwaites. He and Taylor were seen having dinner together a few weeks ago, sparking speculation they might be a couple, but now it seems like they were just talking about the movie.
This won't be Taylor's first acting job, but it will be her biggest. She was on an episode of Zooey Deschanel's TV show New Girl and also voiced a character in the animated movie The Lorax.