Caila Thompson-Hannant, better known by her stage name Cecile Believe (formerly known as Mozart’s Sister), is a singer-songwriter from Montreal, Québec, Canada.

Having been part of several Canadian bands (Shapes and Sizes, Miracle Fortress and Think About Life) between 2005 and 2011, Thompson-Hannant split from Miracle Fortress in 2011 to establish her solo project, Mozart’s Sister.

Her debut LP, Being, was released in 2014 through Sufjan Stevens‘ Asthmatic Kitty Records, which was received with mild-to-positive reviews.

Thompson-Hannant took another break after her debut to tour and write songs, which culminated in her sophomore LP, Field of Love. Released in 2017, it was met with more praise than her debut. The same year, she relocated to Los Angeles.

In 2018, Thompson-Hannant provided writing and vocals on good friend SOPHIE’s debut album, Oil of Every Pearl’s Un-Insides. Her contributions to the project earned her a Grammy nomination for Best Dance/Electronic Album at the 61st Annual Grammy Awards.

Though she initially changed her social media handles to “Cecile Believe” in 2018, her first release under the new moniker was “Last Thing He Said to Me in Person,” in 2020.

Aside from her previously mentioned collaborations, Thompson-Hannant has contributed vocals and production to various other electronic projects, including tracks for TOPS and Kane West.