WATCH: Sia revives 'Unforgettable' for 'Finding Dory' end credit

MANILA, Philippines - Singer-songwriter Sia is on board “Finding Dory,” performing the film’s end-credit song, “Unforgettable."

American songwriter Irving Gordon wrote the song in 1951, and in 1992 won a Grammy for it when Natalie Cole included the tribute to her late father on her album of duets. “Unforgettable” remains revered worldwide today.

Five-time Grammy nominee Sia agreed to sing the song when the voice of Dory herself made the request. “Dory's story makes me teary,” says Sia. “When Ellen asked me, I couldn't refuse!”

Director Andrew Stanton has long been a fan of the native Australian performer.

“In the same way Robbie Williams did his own unique twist on a classic song for ‘Finding Nemo,’ Sia captures the soulful truth of the Nat King Cole classic ‘Unforgettable,’ and makes it all her own,” said Stanton.

“They are a perfect complement to one another, just like the two films,” he added.

Disney-Pixar's “Finding Dory” finds Dory living happily in the reef with Marlin and Nemo about a year after their life-changing adventure.

When Dory suddenly remembers that she has a family out there who may be looking for her, she recruits Marlin and Nemo for a life-changing adventure across the ocean to California’s prestigious Marine Life Institute (MLI), a rehabilitation center and aquarium.

In the effort to find her mom and dad, Dory enlists the help of three of the MLI’s most intriguing residents: Hank, a cantankerous octopus who frequently gives employees the slip; Bailey, a beluga whale who is convinced his biological sonar skills are on the fritz; and Destiny, a nearsighted whale shark.

Deftly navigating the complex inner workings of the MLI, Dory and her friends discover the magic within their flaws, friendships and family.

“Finding Dory” swims into Philippine theaters on Thursday, June 16. The film is distributed by Walt Disney Studios Motion Pictures International through Columbia Pictures.