Sia has joined Ellen DeGeneres deep beneath the waves with her new Finding Dory single.

The masked singer contributed a cover of “Unforgettable” to the Finding Nemo sequel’s soundtrack, and she appeared on The Ellen Show today (May 20) to perform her rendition of the song for the first time.

Written by Irving Gordon and popularized by Nat King Cole in 1951, “Unforgettable” is a perfect choice to play over the end credits of the aquatic Pixar flick given the title character's little problem with remembering things.

DeGeneres, who voices Dory in the film, took a moment to interview Sia about her involvement. “I can’t imagine anyone else doing this,” DeGeneres said. Sia was more than happy to contribute to the movie: “Dory’s story makes me teary,” she said.

Finding Dory hits theaters on June 17. Watch Sia’s performance below.