The Hollywood hunk was holidaying with friends in the sunshine country when the mistake happened. He was determined to show off his superior surfing skills so paddled out into deep water, but froze when he saw a dark shadow swimming below his board.
He immediately alerted his friends to the threat, and began furiously paddling to shore. In his haste to get onto dry land Zac tipped over, and plunged into the freezing water. "I thought I was going to get eaten alive," he told friends.
He eventually managed to climb back onto his board, and raced to the shore. Once there, he couldn`t help noticing his pals were giggling at him. When one told him to turn around Zac obliged, and couldn`t believe what he was seeing.
"A playful dolphin was happily frolicking in the waves," a source laughed.