Mitchell

“You are your mother's trueborn son of Lannister."

"Am I?" the dwarf replied, sardonic. "Do tell my lord father. My mother died birthing me, and he's never been sure."

"I don't even know who my mother was," Jon said.

"Some woman, no doubt. Most of them are." He favored Jon with a rueful grin. "Remember this, boy. All dwarfs may be bastards, yet not all bastards need be dwarfs."

And with that he turned and sauntered back into the feast, whistling a tune.

When he opened the door, the light from within threw his shadow clear across the yard, and for just a moment Tyrion Lannister stood tall as a king.”
― George R.R. Martin, A Game of Thrones