Osbourne, 29, kept the drama in the past as she shared a photo of herself jokingly choking the "Applause" songstress. "#peace at last @ladygaga," the newly single star wrote via Instagram. John, 66, meanwhile, can be seen laughing behind the two women.
An eyewitness tells Us Gaga asked to greet Osbourne at the star-studded bash, hosted by Audi. "Elton and Gaga were just looking for you to come and say hi," Kelly's mother, Sharon Osbourne, was overheard saying. The E! Fashion Police star and Gaga, 27, then hugged and smiled while chatting next to the "Your Song" crooner.
Osbourne and the "Born This Way" singer's feud first began in 2009 when Osbourne called Gaga a "butterface." She received death threats from the singer's "little monsters" and later called Gaga a hypocrite in the July 2013 issue of Cosmopolitan.
"I loved Lady Gaga. I totally believed in everything she stood for, until I realized she's a great big hypocrite," she said at the time. "Don't say, 'When you see bullying, intervene,' while letting your fans send me death threats. If my fans did that, I would not stand for it." (In January 2013, Sharon also called Gaga a "bully" and "hypocrite" in an open letter.)
The arguing continued when Gaga sent Osbourne a birthday cake via Sharon, 61, during a visit to the X Factor UK set that October. "Not to be ungrateful but why would you send me a birthday cake via my MOTHER in a country half the would away? #JustSendItToME #LoveNotWar." She later apologized: "@ladygaga I acted like a child last night. Just not into publicity stunts call me & we will end this like adults I don't want 2 fight anymore."