Jack, who's a new dad himself, shared an adorable Twitter photo of his 18-month-old baby Pearl dressed as grandpa Ozzy.
The caption reads: "The Princess of Darkness."
Jack, 27, and his wife Lisa recently suffered the tragedy of losing their second child from a miscarriage.
Hopefully this precious face helped boost their spirits.
She's definitely an Osbourne.
The Princess of Darkness pic.twitter.com/bZDj8XDLI3— Jack Osbourne (@JackOsbourne) October 4, 2013