Competition winner Gregory Stevens

His story was based on the Welsh legend of the dog Gelert, which gave its name to the north Wales town of Beddgelert.

In the legend, Gelert was mistakenly killed by his owner, a King who thought the dog had savaged his baby son.

In the new version of the story, the ghost of Gelert returns to the village of Beddgelert.

Extra role

Despite its Welsh setting, the film was shot in Ireland where Gregory was given a part as an extra in the short film, as the 80-person crew adapted his creation for the small screen.

"It was strange to see what I had written," said Gregory Stevens.

"There was a cafe that was exactly as I had imagined it, and there were chairs with the names of the characters on them," he said.

The Return of Gelert will be shown on the Disney Channel on the 18 January.