Under any circumstance, it may not be best to mess with Britney Spears.

According to the Daily Mail, on Wednesday, during the pop star's "Piece Of Me" show at Planet Hollywood in Las Vegas, a fat-shaming heckler allegedly belted, "Fat b**ch!"

Shortly after the rude comment, Britney, at the verge of her "Till The World Ends" number, let out, "F***ing a**hole!"

Reportedly, the man was beside the stage, indicating good chances of the Pop Princess hearing such foul remarks. Nevertheless, Britney went into her 2011 single like any normal day, live with energy.

However, the Daily Mail cited Twitter netizens, who appeared to claim that Britney actually said "a**holes" -- meaning, she's firing back at more than one person.

In an updated report by TMZ, it is said that the man who yelled "fat b**ch" had been "so far back there's no way Britney could have heard him."

Now the big question remains: Did Britney respond to the shaming heckler, or is it for the crowd in general?

"Sources who work on the show" told TMZ that the singer reacted to another comment, made by someone in the audience. Unfortunately, no one seems to be sure what that comment actually is.

At the end of the day, only Britney can tell. But, does it still matter?

Well, Britney's definitely back in the spotlight, as fans anticipate her collaboration with Iggy Azalea in "Pretty Girls." The song is expected to debut, live, at the Billboard Music Awards on May 17, Hollywood Life reported.

An unnamed insider told the outlet, "They are definitely going to have a performance together and they are finalizing a deal with the people at the Billboard Music Awards to have it during that show."

Britney and Iggy were spotted filming the song's 80s-inspired music video earlier this month. In this photo (via Hollywood Life), the girls are seen having fun in a jeep, celebrating life at the moment.

Iggy, who's been "super excited" about the song, told Access Hollywood recently, "I'm gonna be co-directing the video next week... So that's been awesome, not only just getting to work with [Britney] and write the song, but being able to have something to do with the visual..."

"It's just been great. It's just been an honor that she would let me do that for her, so I'm super excited," the rapper went on.

To whom was Britney's F- and A-bombs for? Did she say things right? Sound off in the comments section!