why they were call tomas and yerlisa？

I watched "The Maze Runner" last week. It was very interesting, but I don't understand why the actors playing the leading roles are called Tomas and Terlisa. because Years befor ago I have read a the novel, "The Unbearable Lightness of Being" and the actors playing the leading roles were also called Tomas and Terlisa... it is really funny, isn't it?