These countertenors are precise opposite numbers to Broadway's "belters" - women who sing exclusively in the "male" register of chest voice.
Musically, it is a disco-pop song sung exclusively in falsetto.
The group, who sing exclusively in English, makes music that can be characterized as folk-rock or melodic pop, but is also influenced by psychedelia and oriental music.
They recorded two versions of the song, one with original French and English lyrics and other sang exclusively in Russian.
As the new album's title indicates, Ekdahl exclusively sings songs written by her husband, primarily in the bossa nova style.
And he sings exclusively about the all-purpose subject: love.
He sings exclusively through the medium of the Welsh language.
Jambyl sang exclusively in the Kazakh language .
This choir sang exclusively in Gregorian chant, and "all we did was sing funerals," he said.
It is a cumbia-based style traditionally sung exclusively by women.