"I went to defend the climbing frame from some aliens, and the younger kid told me I was standing in lava," Stuart said, as per CBC Radio.
"So I jumped up on a see-saw, and then I was letting the aliens in. And it just went backwards and forwards and backwards and forwards.
"And it just struck me that... basically, this was an episode of Bluey that I was in."
With that, he emailed a pitch to the show's creator Joe Brumm, whom the The Guardian reporter had previously interviewed.
This inspired Surprise, which sees dad dog Bandit agree to play two different games with Bluey and her sister Bingo simultaneously.
Stuart has a credit at the end of the show, much to the delight of his children.
"My oldest kid went to school and announced to his classmates that the episode had my name at the end of it, and the teacher put it on for them," Stuart said.
"Now I'm a real big deal. You have no idea. Yeah, I'm a real big shot on the playground."
Fans of the hit show were left worried about the fate of Bluey when a 'For Sale' sign appeared outside the beloved home at the end of the finale.
Luckily, the producer Sam Moor confirmed that the globally adored series is here to stay with "many more surprises in store" for fans.
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