VIDEO: Sandra Bullock Plays 'Never Have I Ever' on 'Ellen' – and Still Plays Coy About Mooning Scene

Sandra Bullock is known for being private, doing her best to keep her family out of the spotlight – and after playing a round of “Never Have I Ever” with Ellen DeGeneres and her Our Brand Is Crisis costars, it’s clear that it’s not because she has anything to hide. Bullock really is as modest as she seems.

As DeGeneres asked revealing question such as “Never have I ever had sex on a beach” or “Never have I ever been kicked out of a bar,” Bullock, 51, – who played along with costars Anthony Mackie and Billy Bob Thornton – found herself being the only one showing the “I have never” side of her paddle.

While the game might have given Mackie a crisis of conscience – “Dang, I’m an awful person” he joked after turning his “I have” paddle numerous times – the actor challenged his Oscar-winning costar when she said she had never hooked up with anyone in the back of a limo.

“What, you didn’t go to prom?” he asked Bullock. “What did you do at prom?”

“I came home early because we broke up two weeks before!” she said in response as she pretended to start crying.

Some things the actress did admit to? Lying to a cop, and of course, lying on a talk show.

“Oh, pshh, yeah,” she said matter-of-factly.

Because the actors were so honest, Shutterfly donated $15,000 to Warren Easton Charter School in New Orleans. Bullock adopted the school after it was severely damaged by Hurricane Katrina in 2005, and it just so happens to be the high school that Mackie graduated from.

And while Bullock was forthcoming during the game, she wasn’t quite so revealing when it came to discussing one particular scene from Our Brand is Crisis – the mooning scene.

The actress continues to remain tight-lipped on whether she used a butt double for the scene.

When DeGeneres asked her if it was her butt, she played coy.

“Well it depends,” she said. “On how good it looked.”

Thornton said that the only way to get Bullock to tell the truth is if enough people compliment her for the revealing scene.

“She’s been holding out on that because she really wants a consensus first,” he said. “If everyone says, ‘Wow what a butt,’ she’s going to own up to it.”

Haylie Duff on the Breastfeeding Issue That Turned Her Baby Into a ‘Nightmare Child’

Mackie recalled the day they were filming the scene, in which Bullock moons someone from inside a bus, saying that she was a little too comfortable with the nudity.

“It was like, all right Sandy, just pull your pants up, please,” he joked.

Bullock admitted that because it was especially hot outside while filming, she had no problem shedding the extra clothes.

“I was just dropping trou and hanging it out the window,” she said. “Not even thinking who’s on the other side to see that mess.”