Sydney Sea Life Aquarium's same-sex penguin couple has welcomed their first baby chick.

Sphen and Magic captured hearts everywhere after being given their very own egg to foster.

Aquarium staff announced on Friday morning that Sphen and Magic had officially become parents. The chick is still without a name, but is currently being called "Baby Sphengic."

A pair of gay penguins at Sydney Sea Life Aquarium have become "doting" parents after their foster egg hatched.

The same-sex couple, Sphen and Magic, became a viral sensation when they were given an egg to incubate together, and keepers discovered they were "absolute naturals" as parents.

And today, the news broke that the egg has hatched and they have become the aquarium's first pair of dads.

Two weeks ago the aquarium's "fabulous love birds" captured the world's attention when they became celebrities on Twitter.

And on Friday morning, keepers were proud to announce that their still-unnamed chick, currently being called Baby Sphengic, was born.

The 91g chick was born at 5:45 p.m. on October 19.

—Sea Life Sydney Aquarium (@Sydney_Aquarium) October 26, 2018

It is the first sub-Antarctic penguin chick to be born at the aquarium since the colony first joined in 2016.

The aquarium said the chick will "act as an ambassador for its generation" at Sea Life Sydney, and "help educate the public on the precious species and the plight that they face in the wild".

Staff say the two are "absolute naturals." Sydney Sea Life Aquarium/REUTERS

A spokesman said: "After proving they were absolute naturals when incubating a dummy egg given to them by Sea Life Sydney staff, the couple, collectively known as Sphengic, fostered a real egg from another couple who laid two during the 2018 breeding season.

"The fostered egg has now hatched, and the loving foster parents are co-parenting exceptionally well to raise their young."

Tish Hannan, supervisor at the aquarium's penguin enclosure, said: "Baby Sphengic has already stolen our hearts! We love watching the proud parents doting and taking turns caring for their baby chick."

"With that said, the first 20 days of a penguin chick's life are the most vulnerable so it is extra important the chick is very happy, healthy and well fed by his parents.

"We can't wait for the world to fall in love with Baby Sphengic like they did with our amazing same-sex couple, Sphen and Magic!"

The incubation period for sub-Antarctic Gentoo Penguins lasts approximately 36 days, with the small beak of the tiny Gentoo chick "pipping" out of its egg taking up to three days.

The chick will now stay with its dads for the first five to six weeks of his life where they will feed him up to 10 times a day. Once he is big enough, it will start to lose its baby penguin fluff, start growing its adult feathers and begin its swimming lessons, keepers said.

The penguins are not the first same-sex couple to incubate an egg in the world. Last month, a same-sex couple were given an egg to incubate after their parental instincts were so powerful, that they "kidnapped" the baby of another couple.

Unlike the King Penguin population who incubate eggs on their feet, once laid, the expectant Gentoo parents keep their eggs warm on pebble nesting rings scattered throughout the Macquarie Island inspired exhibit.

They swapped parental duties daily, as one of the pair incubated the egg and the other patrolled the perimeters of the nest, warding off any potential pebble thieves or overly inquisitive neighbours.

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