Rock wildman Ozzy Osbourne was hit with an $80,000 lawsuit after mistakenly throwing a bottle of water at a baby.

The Black Sabbath star was performing a show in Phoenix, Arizona as part of his annual Ozzfest tour when he spied a woman in the audience holding a one-year-old child.

The sympathetic singer tried dropping a bottle of water to the woman to help her stay cool in the blistering heat - but the container struck her baby and she later filed a lawsuit against the star.

Osbourne's former guitarist Zakk Wylde tells music website Noisecreep.com, "I remember an Ozzfest show in Phoenix. Some bonehead lady has like a one-year-old there. Leave the f**king kid home - or I'll take care of the baby backstage! Just get out of the heat, you idiot!"

"Oz sees her and feels bad for the kid because Oz is a good guy. He tosses a bottle of water down. It hits the kid. Bam - $80,000 lawsuit."