The fashion correspondent sported black diamond nail polish from a bottle of varnish worth a quarter of a million dollars.
Containing 267-carats of black diamonds, the Azature varnish was released last month by Los Angeles-based luxury jeweller Azature.
With just one bottle ever produced, Osbourne and Jennifer Lopez are the only two people ever to have worn it.
The 27-year-old uploaded a photo of the bottle prior to the awards ceremony, adding: "About to get a $250k manicure w nail polish made w black diamonds made by @azature.
"So excited & honored but absolutely s---ing myself to have that much money on my nails!"
"I'm the only person they let wear it, it's in a safe upstairs in the hotel room. I couldn't believe it. I have not touched a thing all day."
The man behind the manicure, celebrity stylist Nicolas Bru, explained the look: "I was very inspired by the neo-goth looks presented on the runways this fall, and I wanted to mix that up with red carpet glamour."
Azature, the designer behind the brand, said that the black diamond is the "ultimate fine jewel".
"One day I thought, 'why not showcase this style on nails?' So I developed a Black Diamond Nail Polish with the same attention and quality as my jewellery in order to preserve the elegance of the black diamond."