(CNN) - The bands *NSYNC and Queen might not have a lot of crossover in the music world, but they do at the Denver Zoo where two same-sex flamingos -- named Lance Bass and Freddie Mercury -- share a love story.
On Tuesday, four days before the start of Denver PrideFest celebrating the city's LGBTQ community, the Denver Zoo shared a post on Facebook about the two male flamingos, who the zoo says have been a couple since 2014.
Lance, a Chilean Flamingo, and Freddie, an American flamingo from the Dominican Republic, perform courtship rituals, like "head flagging," and live in a nest mount they built on a communal island, according to Mary Jo Willis, a bird expert at the Denver Zoo.
Freddie is about 49 years old and arrived at the Denver Zoo in 1978. Lance hatched at the Denver Zoo in 2001, Willis said.
Before the two coupled, Willis said, Freddie was paired with a female American flamingo.
Although the pair can't reproduce, the zoo said they may still expand their family. The couple can "act as surrogate parents if a breeding pair is unable to raise their chick for any reason," the zoo said on Facebook.
In the meantime, Willis said they have been getting parenting practice by incubating a "dummy" egg.
They wouldn't be the first same-sex avian couple to raise a chick. Last year, a gentoo penguin pair in Sydney, Australia hatched an egg laid by another couple.
And it isn't unheard of in a variety of bird species for two males in a pair to raise a chick, including Humboldt and African penguins and lorikeets, Willis said.