A huge king penguin chick named Pesto, who weighs as much as his parents combined, has become a social media celebrity and a star attraction at an Australian aquarium.

Weighing 22kg at nine months old, Pesto is the heaviest penguin chick the Sea Life Melbourne Aquarium has ever had, education supervisor Jacinta Early said.

By contrast, his doting parents Hudson and Tango weigh 11kg each.

Pesto’s global fame has grown with his size, with more than 1.9 billion people around the world viewing him through social media, an aquarium statement said.

Pesto with other penguins
Pesto weighs as much as his parents combined (Rod McGuirk/AP)

He ate more than his own body weight in fish in the past week with a total of 24kg, Ms Early said.

The veterinary advice says that quantity of food is healthy for a chick approaching adulthood.

His growth will plateau as he enters his fledging period. He has started to lose his brown feathers and will replace them with the black and white plumage of a young adult.

His keepers expect him to trim down to around 15kg in the process.

“He’s going to start losing that really adorable baby fluff. It might take him one to two months to really get rid of it. Then he’ll be nice and sleek and streamlined,” Ms Early said.

But she expects Pesto will remain recognisable as the sought-after TikTok celebrity he has become for another two weeks.

“Such a small head for such a big body,” one admirer remarked on Friday as a crowd gathered against the glass of the penguin enclosure at feeding time.

Born on January 31, Pesto was the only king penguin chick to hatch at the aquarium this year and the first since 2022, a year when there were six. The reason why there was none last year is not clear.

Adult king penguins weigh between 9.5kg and 18kg, according to the Antarctic and Southern Ocean Coalition, a global environmental group.

They are the world’s second largest penguin species, after the emperor penguin.