Lupita Nyong'o would never gain 100lbs for a role.
The 33-year-old actress and her 'Queen of Katwe' co-star David Oyelowo - who piled on 30lbs to play Martin Luther King Jr. in 'Selma' - played a game of 'Dwheel Breakers! Career Edition' during an appearance on 'Watch What Happens Live' and revealed what they would and wouldn't do for their art.
Asked about the huge weight gain, Lupita said: "I've battled with this one, I have, but I don't think so."
David added: "I gained 30lbs to play Dr. King. I don't think I want to do triple that."
The 33-year-old actress said lots of S&M action would be acceptable - but only if she was "the dominator".
However, David would refuse for the sake of his family life with wife Jessica.
He told host Andy Cohen: "I have four children, so no."
Both stars would work on a location without mobile phone reception for a year, but not in a cold place.
Lupita noted: "That would be quite fabulous actually."
And neither Lupita nor David would exchange a big pay cheque for a bad script.
The actor said: "That is the way to kill your career."
But both would accept stage roles as an 'adult baby'.
David said: "That sounds fun."
Elsewhere on the show, David talked about his trip to Maui with 'Selma' co-star Oprah Winfrey and their boozy nights out.
He said: "Oprah likes shots, she will drink you under the table."
But asked who picked up the bill, he simply said: "She likes me a lot, that's all I'm going to say."
The 40-year-old star particularly enjoyed the fact Oprah is always accompanied by her own "incredible" travelling chefs.
He said: "We mostly talk about food because she has the most incredible chefs in the world.
"Have you ever heard of a Cronut, a mash up between a croissant and a donut? Oh my goodness, I'm literally salivating."