The two pop superstars were perfecting their moves when Gaga's fingernails connected with her pal's cheek, and the moment was caught on camera. It aired during the latest instalment of the "Poker Face" singer's "Gagavision" Internet docu-series.
"I shanked her with my nail by accident dancing," Gaga explains.
"Lady Gaga scratched my eye!" Ariana added. "It's an honour, I hope it scars."
Gaga then chased Ariana, trying to apply Neosporin antiseptic cream to her wound, stating, "Listen to your mom! You have a scratch on your face, you can't get infected before the video! Please let me put Neosporin on it!"
Grande ran off yelling, "Oh my God, you're two days older than me!"