Joke music video The Fox by Norway’s Ylvis 2013’s top YouTube hit

A zany Norwegian music video originally intended as a joke was the most popular video of the year on YouTube.

Since its release on September 3 the clip - featuring people in animal costumes dancing in a forest to the refrain, "What does the fox say?" - had more than 276 million views on YouTube, the website said.

The Fox shot to eighth place in the popular music chart compiled by US music magazine Billboard in October, ahead of major artists such as Lady Gaga and Lana Del Rey.

It even led to a children's book deal for the Norwegian comedy duo Baard and Vegard Ylvis, who first released the music video to promote a TV comedy show.

The brothers, simply known as Ylvis, were not available to comment, but they have previous called their unexpected viral hit a "rubbish song."