The death has been announced of Stephen Hillenburg, the creator of the Nickelodeon animated series SpongeBob SquarePants, who has passed away after a battle with Motor Neurone Disease. He was 57.

In March 2017, the marine biologist-turned-animator announced that he had been diagnosed with Motor Neurone Disease. The disease affects the nerve cells in the brain and spinal cord.

In a statement on Tuesday, Nickelodeon said it was "incredibly saddened" by his passing.

"He was a beloved friend and long-time creative partner to everyone at Nickelodeon, and our hearts go out to his entire family," the statement continued. 

"Steve imbued SpongeBob SquarePants with a unique sense of humour and innocence that has brought joy to generations of kids and families everywhere. 

"His utterly original characters and the world of Bikini Bottom will long stand as a reminder of the value of optimism, friendship and the limitless power of imagination."

Since its premiere on children's channel Nickelodeon in July 1999, SpongeBob SquarePants has become a multi-billion-dollar global phenomenon through the series, big screen adventures and associated merchandise.

A third film is due to be released in August 2020.

There have been many tributes on social media - among the fans authors, animators and actors: