Sharon Osbourne's medical emergency last month was triggered when she fainted on the set of a TV show and remained unconscious for 20 minutes.

The 70-year-old TV star was filming 'Night of Terror' with son Jack in Santa Paula, California when she passed out and was rushed to hospital, but Sharon has now revealed that doctors still don't know what caused the episode despite undergoing a number of tests.

In her first TV appearance since the emergency, Sharon opened up about what happened. Speaking on TalkTV show ‘The Talk’ on Tuesday night (03.01.23), she explained: "I wish I could [explain what happened] but I can't. It was the weirdest thing - I was doing some filming and suddenly they tell me that I felt ... "

Co-host JJ Anisiobi then asked: "Passed out?" and Sharon replied: "Yeah, for 20 minutes. I was in hospital. I went to one hospital, they took me to another hospital and I did every test over two days and nobody knows why."

JJ then asked the star: "So they still don’t know why you passed out?" and Sharon said "No".

After the hospital dash, Sharon's son Jack released a statement confirming his mum had been given the "all clear" and was recovering at home, but he insisted it was up to her to explain what happened.

In a post on Instagram, he wrote: "Ok here is what I’ll say. First things first MY MOTHER WASN’T A EPISODE OF @ghostadventures. She was filming a new episode 'Night of Terror' with me.

"Now that we have made that clear … She has been given the all clear from her medical team and is now home.

"Thank you to everyone who has reached out with love and support. As to what happened to my mum – I’m gonna leave it to her to share about when she is ready."