Apparently, SIA was personally asked by Ellen DeGeneres to cover and perform the theme tune for Finding Dory.
The song used for the highly-anticipated film is Nat King Cole’s Unforgettable. Ellen – the voice of Dory – asked the singer to do the cover
Finding Dory is set six months after the events of Finding Nemo, but this time the story will mostly take place at the Marine Biology Institute of California, where Dory was born. She lives with Nemo and his dad Marlin in a coral reef in the ocean.
When she and her friend go on a field trip to the institute, she recalls memories of her past and family—basically, that she has both—and seeks to find her parents, Jenny and Charlie, portrayed by Diane Keaton and Eugene Levy.
Dory was such a hit with fans that a spin-off film just focusing on Dory will hit in July.
Sia was on the show to perform her version of the classic song (and it’s amazing).
https://www.youtube.com/watch?v=fMVlYk6uNB0