One good turn deserves another, as they say.

"Embrace the power of the Ring... or embrace your own destruction!"

"Hojotoho! Hojotoho! Heiaha! Heiaha!"

Then Beren and Lúthien went through the Gate, and down the labyrinthine stairs; and together wrought the greatest deed that has been dared by Elves or Men. For they came to the seat of Morgoth in his nethermost hall that was upheld by horror, lit by fire, and filled with weapons of death and torment. There Lúthien was stripped of her disguise by the will of Morgoth, and he bent his gaze upon her. She alone of all things in Middle-earth could not be daunted by his eyes; and she named her own name, and offered her service to sing before him, after the manner of a minstrel.

-J.R.R. Tolkien, The Quenta Silmarillion, 1937

Then Beren and Lúthien went through the Gate, and down the labyrinthine stairs; and together wrought the greatest deed that has been dared by Elves or Men. For they came to the seat of Morgoth in his nethermost hall that was upheld by horror, lit by fire, and filled with weapons of death and torment. There Beren slunk in wolf's form beneath his throne; but Lúthien was stripped of her disguise by the will of Morgoth, and he bent his gaze upon her. She was not daunted by his eyes; and she named her own name, and offered her service to sing before him, after the manner of a minstrel.

--J.R.R. Tolkien and Christopher Tolkien, The Silmarillion, 1977