Every child who grew up watching SpongeBob Squarepants will recognize those words as the opening to the iconic Nickelodeon cartoon’s theme song — as well as the pirate painting with moving lips that sings them.

It turns out that those lips belong to none other than series creator Stephen Hillenburg, who died last November from ALS at age 57.

Squidward voice actor Rodger Bumpass revealed the secret at the show’s San Diego Comic-Con panel on Thursday, Entertainment Weekly reports.

“I don’t know if its common knowledge or not, but when you see the opening and there’s that painting of the pirate and there’s lips moving, that’s Stephen,” Bumpass said.

“I think the painting, somebody found in a thrift store somewhere, on sale,” said the voice of SpongeBob, Tom Kenny.

The cast also praised Hillenburg’s legacy, and Kenny said he never “wanted to be in a show so bad” as SpongeBob.

“SpongeBob has conquered the world,” Kenny said.

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“He’s in every county on earth, he’s on every conceivable product he can be on, but… it just reminds me of a time when SpongeBob only existed in Stephen Hillenberg’s desk drawer,” he continued. “I remember when he had me come over to his place and said, ‘I’m thinking about pitching this to Nickelodeon,’ and he took out that, it was just like, wow. It blew my mind. I’d never wanted to be in a show so bad.”

Hillenburg announced that he had been diagnosed with ALS in March of 2017, and his official cause of death was cardiopulmonary failure due to the disease.

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“He was a beloved friend and long-time creative partner to everyone at Nickelodeon, and our hearts go out to his entire family,” the network said in a statement at the time of his death.

“Steve imbued SpongeBob SquarePants with a unique sense of humor and innocence that has brought joy to generations of kids and families everywhere,” the statement continued. “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.”

Hillenburg’s ashes were scattered at sea last December.