Nicole Richie just took to Instagram to wish her 13-year-old daughter, Harlow a happy birthday.

The Simple Life alum shares Harlow, as well as 11-year-old Sparrow, with husband, Joel Madden.

"Here you are at 3 months old. Today you are 13," the proud mom wrote with a never-before-seen throwback of Harlow. "You light up my life with your presence, & have no problem lighting up my bedroom with your bright phone screen. Nothing is better than watching you become the young woman you are."

She added: "I am so lucky I get to be your mom. Happy Birthday to my favourite girl in the world. Now lets go binge watch season 3 of Greys. [sic]