2. Saoirse Ronan Mastered The Piano For Her Role In Byzantium
When it comes to portraying someone who has a skill an actor lacks, this can usually be faked relatively easily so long as the performer can mimic hand movements and make it look real. For something like playing the piano, shooting the actor and then cutting to someone else's hands often works perfectly.
Most actors are fine with doing that, and the audience is never the wiser. James Cameron drew Kate Winslet in Titanic, and there was no way to know it wasn't Leonardo DiCaprio doing the work. It's just one of those things moviemakers do, but for Saoirse Ronan's role in Byzantium, she wasn't about to let someone else perform in her place.
In one scene, she walks up to a piano, sits down, and begins playing Beethoven's Piano Sonata Opus 2, No. 3. This was something she didn't know how to do in any way prior to accepting the role, and it took her only 12 weeks to learn. Not only is that impressive, it's ridiculously impressive given the difficulty in mastering the piece.
Most of the scene is shot so you can't even see that she's actually the one playing, but it's definitely her. She shocked the director by learning the piece, and it's truly mesmerizing to watch the scene, which you can do right now: