I guess it's fair to say that it's been speculated for quite some time that Twilight Sparkle, the central character of My Little Pony: Friendship is Magic, is destined to become a princess of Equestria alongside Princess Celestia and Princess Luna at some point. Some say it'll happen at some point in Season 3, owing that "The Crystal Empire, Part 1" dropped a hint. Some are hoping it won't happen because it could potentially mean the end of the series. Good riddance. It wasn't all that good anyway. Well, here's an image that showcases the signs.
First of all, the screenshots from "The Crystal Empire, Part 1" show the sun and moon behind the two princesses and the stars behind Twilight. Now, should Twilight become a princess, she would obviously become Princess of the Stars, thus completing the circle of the sun, moon, and stars. And if you look closely in the left-hand corner of the image, you can see the closest thing to an official artwork of Twilight Sparkle with wings, meaning she's a Pegasus unicorn like Celestia, Luna, and Cadance. Considering past generations of Twilight, this sort of thing has never been tried before, so who knows what Hasbro is willing to risk for this. At this point, only time will tell what happens. The answers lie ahead in the future.