A celebrated Australian penguin famous for raising chicks as part of an unlikely same-sex couple has died, a Sydney aquarium said on Thursday.

Male gentoo penguins Sphen and Magic caught the attention of zookeepers, and then the world, when they built a nest of pebbles together in 2018.

They were eventually given live eggs to incubate from other penguin couples, hatching chick Sphengic in 2018 and Clancy two years later.

Sealife Aquarium said Sphen -- the older partner in the "same-sex" penguin "power couple" -- had died just shy of turning 12, considered a long life in captivity.

Sphen and Magic were adopted as gay icons in Australia and further abroad, inspiring a float at the Sydney Mardi Gras parade and featuring in the Netflix sitcom Atypical.

But they also had their critics, with some in conservative circles saying the penguins were unwittingly being used to push a political agenda.

Unlike many mammal species, male and female penguins take on the same parenting roles, and share parental duties 50-50.

Same-sex couples between both males and females are not unheard of, although they are often short-lived in the wild.

It was not the first time same-sex penguin couples had adopted eggs in captivity, with a handful of zoos worldwide reporting similar cases.

In 2009, two male penguins -- Z and Vielpunkt -- successfully hatched and reared a chick that was rejected by its heterosexual parents at a zoo in Berlin.

Before them came Roy and Silo, two male chinstrap penguins at a zoo in New York who were spotted frequently trying to mate with each other.