Jackass star Steve-O has confessed he is the guy behind a Sea World freeway sign prank that upset themepark bosses in May (14).

The animal-loving stuntman has revealed he added the 'Sucks' billboard to the Sea World mileage indicator in San Diego, California as a protest against the way killer whales are treated at the aquatic tourist attraction.

Steve-O has now posted a video on YouTube, in which he alters the freeway sign to read 'Sea World Sucks'.