Morissette, 45, welcomed her third child, a boy named Winter Mercy Morissette-Treadway, into the world on Aug. 8. She announced his birth on Instagram soon after, and on Saturday showed a photo of him feeding.
The social media post encouraged breastfeeding, as she used a breastfeeding mother emoji and tagged various people and groups that promote the act: Stop Censoring Motherhood, The Pump Station & Nurtury, Normalize Breastfeeding and The Badass Breastfeeder.
The newborn is Morissette's third child with her husband, rapper Mario Treadway. The couple has another son, 8-year-old Ever Imrie, and a 2-year-old daughter, Onyx Solace.
The 45-year-old singer-songwriter first revealed her pregnancy on Instagram in March.
The Associated Press contributed to this report.