It's an understood rule that patrons are strictly prohibited from using their phones while a Broadway play is in session. However, a handful of rude theatergoers always tend to wiggle their tasteless habits through the cracks. In fact, one recently violated the mandate in a major way, motivating actress Audra McDonald to respond on Twitter.

The incident took place during a recent performance of Frankie and Johnny in the Clair de Lune, while McDonald and her co-star, Michael Shannon, were nude on stage in a simulated sex scene. The audience member, while looking on, snapped a flash photo of the two in the moment.

McDonald, after the curtain call, took to Twitter to share that the disrespectful gesture did not go unnoticed.

"To whoever it was in the audience that took a flash photo during our nude scene today: Not cool," the five-time Tony Award winner tweeted on Sunday. "Not cool at all."

It is unclear whether the audience member who took the photo was escorted out of the theater by security, as this is usually protocol in these instances.

According to Page Six, this was McDonald's first nude experience during a live production. She explained her nervousness about it to the publication back in May.

"This is my first time, so I was scared," she said. "Once the show is going, you don't think about it, you are playing the characters. It's an important part of the story."