Police investigating after Ariana Grande 'maliciously licks' donuts

Security footage showed singer Grande appearing to "maliciously lick" a donut in a shop.

Things you probably shouldn't do as an American pop superstar. One: Say you hate your country and the people in it.

Two -- and this is really the big one: Lick donuts that aren't yours.

Now, police are investigating after security footage showed singer Ariana Grande appearing to "maliciously lick" a donut in a Los Angeles shop, according to media reports.

In the video, originally released to TMZ, the 22-year-old celebrity seems to stealthily touch donuts with her tongue, before jumping up and down laughing. Then, when an employee approaches with a tray full of donuts, the singer turns to a male companion and says loudly, "What the f*** is that? I hate Americans. I hate America."

The singer tweeted an apology-of-sorts after the video went viral on social media.

"I am EXTREMELY proud to be an American," she wrote. "What I said in a private moment... was taken out of context and I am sorry for not using more discretion with my choice of words."

But instead of addressing the alleged donut licking, Grande then added she felt "very upset" about the food habits of Americans and was "frustrated" by child obesity rates.

Local police did not immediately respond to CNN's request for comment, nor did Grande's manager.