"Jour 1" is the opening track from Hildegard's debut album, and follows last month's debut single "Jour 2".
Deland and Ouri describe "Jour 1" as being "about processing by partying, and the clarity that sometimes comes with it."
The eight tracks on Hildegard are named after each day that the duo spent together in 2018.
Hildegard's name is inspired by Hildegard of Bingen, a mystic, healer, composer and 12th century nun.
Last month the duo described the project as "a psychedelic mantra that labours to reconcile the dissociated self by contrasting eeriness and softness".