“Beyond amazing” is how Nicole Richie describes her new life as a mother. “It’s definitely nothing like I could have imagined,” she beamed to Extra last week. But the new mom — who gave birth to baby Harlow in January — may have more than motherhood on her mind.

Nicole was spotted leaving an audition in Toluca Lake, Calif., on April 11, clutching a script. She explained to an onlooker that she was simply “getting back to work”; however, friends of the star are surprised that Nicole, 26, would be willing to jump-start her career again. “Nicole is thrilled with the way things are in her life, and she couldn’t be happier,” one of her friends tells OK!.

While her fiance, Joel Madden, 29, is on the road with his band, Good Charlotte, the pair keep in touch via iPhone. “While he’s away, Nicole is always sending Joel pictures of little Harlow,” the friend says. “Joel responds by calling back and singing little lullabies into the phone, which always makes Harlow giggle and smile.”

Friends have noticed how this domestic lifestyle suits Nicole, who loves low-key, suburban Glendale, Calif., far away from the glitz of Hollywood.

“Nicole really loves living the simple life in Glendale,” a friend tells OK!. “She loves being at home with the baby. Ever since Harlow arrived, Nicole’s happier than I’ve ever seen her.”

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