Sandra Bullock laid down some ground rules for doing nude scene with Ryan Reynolds in The Proposal

Sandra Bullock has been a big name in Hollywood for over thirty years.

And with all that time in Tinsel Town, it's safe to say that she's learned how to speak her mind on a film set.

When it came time to film a nude scene with Ryan Reynolds for The Proposal, the Oscar-winner had some conditions that needed to be met.

Disney/Touchstone Pictures

In case your memory is a little rusty, the scene in question sees a naked Bullock slip after taking a shower and land on a equally naked Reynolds.

Not exactly the saucy scenario you'd have in mind when 'nude scene' is mentioned.

Speaking about the 2009 film on the About Last Night podcast, Bullock said that she opted to do the scene so long as it was for laughs.

It was also stipulated that she would do the scene with a co-star with whom she felt comfortable, and having known him for a long time, The Deadpool star fit the bill.

Bullock explained: "Ryan and I have known each other since we were prepubescent.

"We go way, way, way back."

Showing that she can have a laugh at her own expense, Bullock insisted that she be embarrassed in the scene.

The A Time To Kill actress said: "I was like, ‘I will do this naked scene only if I can be humiliated and funny.'

"You will not see me trying to attempt being sexy naked—in real life or onscreen.

"There's just no point in it! It was for that reason, with a friend that you trusted comedically, and safety-wise I knew I was in the presence of safety."

Podcast host, Adam Ray, went on to ask about the logistics of how the hilarious scene was filmed.

Bullock explained: "Ryan and I have these flesh-colored things stuck to our privates, my hair is strategically over the nipples, and Ryan's little—not little, at all!

"It's just whatever's there, and I don't know because I didn't see it, I didn't look!"

Disney/Touchstone Pictures

We'll take her word for it.

As if the nude scene wasn't uncomfortable enough, the director, Anne Fletcher, decided to throw an extra layer of awkward on top of it.

Bullock recalled: "I hear Anne Fletcher from the darkness go, 'Ryan, we can see your ball sack!'

"I'm like, 'Oh God!' because you wanna look down, but I'm like, 'Don't look down. Don't look down'."

"Everyone in the darkness spun around to see if they could find a monitor. I was like, 'Anne, there's a way to present that information....'"

"But in friendship, you just didn't care; it wasn't my business to look, it's just there, and then Anne just bringing everyone's focus to that area.

"Ryan was just so cool. Unflappable. He is absolutely unflappable."

If Bullock had social media she might want to retract that last statement as earlier today, Reynolds decided to wish her happy birthday by posting the embarrassing - yet hilariously iconic - naked scene to his Instagram.

Classic Reynolds.