Singer-songwriter Sia has covered the song “Unforgettable” for the upcoming Disney•Pixar film “Finding Dory.”

The voice of main character Dory, Ellen DeGeneres, personally asked the songstress to sing the film’s theme - which will be played over the end credits - and was “thrilled” when she said yes.

“I can’t imagine anyone else doing this,” the talk show host told Sia after she debuted her version of the beautiful tune today on “The Ellen DeGeneres Show.”

“Thank you so much for doing this for ‘Finding Dory,’” DeGeneres added.

Sia then explained that she just had to do the cover after being asked. “Dory’s story makes me teary,” she said.

The “Finding Nemo” sequel tells the tale of blue tang Dory as she travels the waters in an attempt to find her family. In addition to the aforementioned DeGeneres, the Andrew Stanton-directed flick also features the voices of Albert Brooks, Hayden Rolence, Diane Keaton, Eugene Levy, Ed O’Neill, Ty Burrell and Kaitlin Olson.

The song will appear alongside Thomas Newman’s score on the “Finding Dory” soundtrack, which comes out from Walt Disney Records June 17. That’s also the same day that the film premieres in movie theaters nationwide.

“Unforgettable” was written by American songwriter Irving Gordon in 1951 and made popular that year by the late Nat King Cole. Forty years later, the song was uniquely remixed to create a duet between Cole and his daughter Natalie (who died last year). At the 34th Annual Grammy Awards in 1992, the song won three trophies: Song of the Year, Record of the Year and Best Traditional Pop Vocal Performance.

Watch Sia singing “Unforgettable” on “Ellen” below.

The five-time Grammy nominee announced earlier this week her plans to hit 22 North American cities on the Nostalgic for the Present tour, which will be her first live trek in five years. The tour - in support of her latest album, “This Is Acting,” which came out earlier this year and features the single “Cheap Thrills” - will feature support from Miguel and AlunaGeorge. The first gig is in Seattle Sept. 29 and the last is Nov. 6 in Austin, Texas.