Ozzy Osbourne's son JACK feared for his life while participating in a Spanish bull-racing festival for his new reality TV show, after he witnessed the animal rip out another man's intestines.

The formerly chubby son of the Black Sabbath rocker has been enduring a number of dangerous sports for his new British TV series JACK OSBOURNE ADRENALINE JUNKIE.

After seeing the horrific bull attack only a day before, the 19-year-old believed his life was over when he fell to the ground as the bull was charging towards him.

He says, "Those f**king bulls kill people. I saw this guy get his intestines ripped out the day before I did it.

"This bull hit him square in the gut and he was just lying there in this pool of blood.

"I almost got trampled, because a bunch of people in front of me fell over, I slipped and there was this huge pile-up."