Credit: Mark Davis/NBC

Ariana Grande took to the iHeartRadio Awards stage last night, May 1, to prove that the new grown-up vibe she premiered at the Radio Disney Music Awards is here to stay. The Polly Pocket-sized diva — all credit goes to Lucy Hale on this apt description — performed her unstoppable new single “Problem” featuring Iggy Azalea, and busted out some sexy moves that were a bit of a departure for her… so much so they even had Rihanna giggling in her seat!

Everyone was buzzing today about Rih’s reactions to the dance moves, which came about midway through the performance. In the beginning, the “Can’t Remember to Forget You” singer was bobbing along to the catchy tune. But as soon as Ariana started dropping it low (well, for her), cameras capture Rihanna giggling at the unusual sight.

Some were saying that this was the risqué pop star throwing shade at her younger peer, but we beg to differ. It’s more likely that she was just a little surprised at the out-of-character choreography. She even looked like she was blushing a bit!

RiRi had a good sense of humor about all the faux drama, however, as she took to Instagram to share a photo of herself giggling, with a winky face caption. See? She’s just having a little fun!

Do you think Rihanna’s giggles were in good spirits or loaded with shade? Share your thoughts in the comments below.

Credit: AOL Photo: Ariana Grande Strips Down For iHeart Radio Performance (VIDEO)