The star, who has earlier dyed her strands in turquoise-green and bright pink, debuted her latest colour in LA, reported People magazine.
Duff, 27, recently revealed to Ellen DeGeneres that her son Luca is very opinionated about her hair.
"Luca is very particular about how he likes my hair," she shared. There's absolutely no buns on my head, no ponytails.
"I'll have a ponytail and he's like, 'Um, hair down, mom. Hair down, please'. At least he knows what he likes... He saw (my mermaid hair) and he's like, 'Is your hair green, mom?' And I'm like, 'That's right, it's green'. And he's like, 'Wow'," she had said.