Probably Rebecca Romijn on the set of the X-Men franchise.
Every day she had to spend 9 hours in the make-up chair before she could even start acting and then had to go back to the chair to remove the makeup.
And by every inch I really mean EVERY inch:
She loved it though and thought of it as her being paid to endure the exhausting, and at times painful, make-up process and the acting as being an added bonus. She is even willing to reprise the role as long as she can get the same make-up process again so that she can get right back into the character.
She was an absolute badass in the movies and I can't imagine anyone playing the character better than her.
Sorry, not sorry, Jennifer.
Thank you for reading.