Ozzy Osbourne regards tea as a "magic potion".

The legendary rocker knows having his favourite hot beverage before performing isn't good for his voice, but insists on indulging in a mug of the caffeinated drink before taking to the stage.

He said: "Chocolate thickens the Saliva, which isn't good news if you've gotta recite Shakespeare or sing 'Iron Man'.

"Having said that, you're not supposed to drink tea either but I still do before gigs. It's not very rock and roll, but it's like a magic potion to me."

Ozzy - who is married to TV personality Sharon Osbourne - also revealed he relies heavily on caffeine to fully get himself ready for the day.

He admitted: "The best way to wake yourself is to brew a pot of fresh coffee, then run it through the machine a second time using the old grounds.

"While you're doing that, make an espresso then add that to a mug of the double-brewed coffee. In my house, we call it a red-eye.

"Drink one first thing Monday morning and you'll be bright-eyed and bushy-tailed for the rest of the week."