3. Aimee Richardson (Myrcella Baratheon)
The Replacement: Nell Tiger Free
Even though she was supposedly Jaime's favourite secret child, Myrcella initially had very little to do in Game Of Thrones. Her impact on the show's first few seasons amounted to little more than a couple of very brief appearances before she was unfortunately shipped off to Dorne. Back then she was played by Aimee Richardson, who was originally cast as a stand-in only for the pilot's auditions.
Unfortunately for Richardson, when it came time for the show to head to Dorne to catch up with her, she was no longer required and was replaced by Nell Tiger Free. After the recasting announcement, she took to Vine to post a video showing her begging on the side of the road and wearing her princess tiara, while holding a sign saying "Princess for hire".