Washington, Jan 22 : Mariah Carey is surely a dedicated sister-in-law-the singer is doing a duet with hubby Nick Cannon's younger brother to promote his new album.

The `Hero' hitmaker is lending her voice for a song in Reuben Cannon's new album.

"Reuben and Mariah are doing a duet together for Reuben''s first album," E! Online quoted an industry source as telling.

The source added: "They are meeting at the end of the month with Mariah''s record label, Universal Music Group, to seal the deal, and Reuben is thrilled."

Reuben is halfway through recording his album for Lavert Entertainment, and is slated for release later this year.

While the singer and hubby Nick Cannon made no comments on the collaboration, a Reuben rep said: "Reuben Cannon is working on some really amazing things right now." (ANI)