KUALA LUMPUR, Sept 24 ― Visitors to the Bronx Zoo in New York were left red-faced when a frisky gorilla was filmed performing oral sex on its partner.

New York Post reported that the clip had gone viral on social media but experts said the act was normal.

The videographer, who declined to be named, said the visual was captured while he was visiting the zoo with his family.

"I was in the gorilla exhibit with my four-year-old daughter and niece.

"My wife had to stay out of the exhibit with my sleeping son, so I wanted to capture a lot of videos. Then this magic happened,” he said.

The footage shows the giving simian servicing its partner while they’re splayed out on the ground as onlookers guffaw and turn their children away.

Representatives of the zoo, who were initially unaware of the video, had no comment when contacted.