Click to see Spoiler:
Oberyn Martell!!! :yay

In other casting news, we'll also see a THIRD actor playing Gregor Clegane and a second actor playing Daario Naharis. They're also aging Tommen and have recast the part. I wonder if Myrcella will be played by a new actress when we finally see her again.

I'm also super excited about Indira Varma being cast as Ellaria Sand. I love her and I love the character.