How Aubrey Plaza accidentally flashed Robert De Niro

Zoey Deutch and Aubrey Plaza in a scene from the film, Dirty Grandpa.

Actress Aubrey Plaza broke the ice with Robert De Niro while shooting their sex scene in Dirty Grandpa by accidentally flashing her breasts.

The Parks & Recreation star, 31, initially auditioned to play Zac Efron's fiancee in the raunchy new comedy, but after reading the script, she decided to try out for De Niro's unlikely love interest instead.

The idea of getting close to the movie icon made Plaza nervous and she admits things started rather awkwardly as they prepared to get intimate.

"It was scary, it was an entire day of us just pretending to f**k each other...!" she told US talk show host Seth Meyers. "It was crazy. There were so many weird moments but he was so cool about it and so professional and everything."

Plaza reveals producers rigged her bra to pop open for one scene and didn't bother to remove the contraption when they changed their minds about including the stunt when cameras started rolling.

"I felt bad for him because (it was) the very first thing that happened, before we even started doing anything," she said.

"Originally my bra was meant to pop off and it was meant to be this gag; then they decided at the last minute they were not gonna do that, but they had rigged my bra anyway, and were like, 'It won't pop off, it's fine.'

"The very first take, they were like, 'Action!', and he (De Niro) went towards me and it just went, 'Pop off!', and I was like, 'Argh!' So that's how we started the day. At least we broke the ice!"

It wasn't the only cringe-worthy moment Plaza had to endure with the legendary actor.

"He's a very classy guy, he gave everyone a start gift," she said.

"I believe it was a very expensive bottle of wine and a little card that said, 'Break a leg', or something, and I was like, 'Should I get him a gift?' I didn't know him, we'd never talked, and I was really scared of working with him... but I was like, 'I'm gonna do something really crazy', and I took a real slutty picture of myself in my trailer, in character, and then I printed it out and I put it in a book of zen Buddhism. And then I slipped it under his trailer door with a little note that said, 'Happy shooting', or something, and then I waited.

"I didn't hear anything about it for a week and I was terrified that maybe I'd made a mistake and maybe I was gonna get fired... and then he kinda just casually came over to me, like, a week later and he was like, 'I got your book...' I put the picture on page four and he was like, 'I only got to page four, but it was very good,' and then he walked away."

- WENN