Watch: Sharon Osbourne is in quarantine after her young granddaughter tests positive for Covid-19
The 67-year-old TV star – who has previously battled colon cancer – filmed her appearance on US panel show The Talk over video link on Monday, where she revealed her youngest granddaughter Minnie, two, had been diagnosed with COVID-19.
Osbourne said: "I was meant to be in the studio, I was so looking forward to it.
"And then, unfortunately, one of my granddaughters has come down with COVID. She's okay; she's doing good. I don't have it.
She added: "Her daddy doesn't have it. Her mommy doesn't have it. Her sisters don't. She got it from somebody who works for my son.
"And it just goes to show you, she's three years of age, that children can get COVID."
Jack Osbourne, 34, lives with multiple sclerosis (MS) and some patients with MS are considered high risk.
He has three daughters with wife Lisa Stelly – Pearl, eight, Andy, five, and Minnie.
Osbourne said that after coming into close contact with someone who has been diagnosed with coronavirus, she was following protocols and self-isolating, despite testing negative for the virus herself.
She said: "Oh my Lord, I want to see you guys so bad. I've got one more week left of quarantining and then I'm out.
"And as I say, I don't have it. I keep testing negative, but, you know, you have to be safe."
Osbourne added that her son Jack was "equally as upset because he was planning on coming to the studio with me just to wish you good luck."
Her husband Ozzy Osbourne, 71, revealed in January this year that he has been diagnosed with Parkinson’s disease.
Back in March, daughter Kelly, 35, admitted she was worried about both parents as they are considered high-risk.
She wrote on Instagram: "Both of my parents are high risk especially my dad. If I would have known 3 weeks ago when I sent them off to panama that that was gonna be the last time I got to hug and kiss them for a while… I would have held on a little longer. However these are the sacrifices we must make.”