Brown, 31, gave birth to Angel Iris Murphy Brown on April 3 in Santa Monica, Calif. She listed Murphy's name on the birth certificate.
She said the name was inspired by a number of things.
"Angel, as she was my little angel through my pregnancy. Iris, as it's my grandma's name, Murphy because he's the dad, and Brown, because I'm the Mum!" the statement said.
Murphy, 46, has said he's not sure he's the father.
Brown, known as Scary Spice when she was in the megahit group of the '90s, has an 8-year-old daughter, Phoenix Chi.
Murphy, whose screen credits include "Dreamgirls," has five children from his marriage to Nicole Mitchell Murphy.