Halsey posted on Instagram in support of World Breastfeeding Week. The photo shows her sitting in the middle of a field, with her blouse open, breastfeeding her newborn.
The global campaign was launched in 1992 to raise awareness and spread information about breastfeeding.
Halsey gave birth to her first child with boyfriend Alev Aydin on July 14. They named her Ender Ridley Aydin.