The svelte mother of two is Marie Claire UK's March cover girl, showing off her long, dark rock 'n' roll locks and post-baby body in a fashion shoot by photographer Ben Watts (brother of actress Naomi Watts).
In the spread, the 28-year-old reformed bad girl dons a Versace skirt dripping with metal fringe, a fluffy ballerina-style dress by Giles Deacon and skinny grey Mardou & Dean jeans paired with a black leather jacket from her Winter Kate label, named after 2-year-old daughter (with rocker Joel Madden), Harlow Winter Kate Madden.
"Clothing was something I always wanted to do," Richie tells the magazine. "I've been pulling tear sheets from magazines since I was a little girl."
As for juggling two kids while trying to grow a fashion empire, which includes a jewelry line, the fashion brand House of Harlow 1960 and the soon-to-be-released Winter Kate clothing and footwear collections, Richie says it's not a problem.
"I'm a Virgo and I'm really good at scheduling. So there are 24 hours in a day and I'm up at 6:30 am every day anyway," she reveals, before explaining she doesn't rely on a live-in nanny like most A-listers. "Not full-time, but I do have someone that helps me right now and, well, I have my mom, who's here."
Aside from fashion, Richie also discussed rumors that her super-slim frame is due to an eating disorder.
"I definitely felt it was a little unfair to say someone has an eating disorder when they don't," she says of the media coverage over the last few years. "It's extremely insulting and irresponsible. An eating disorder is serious and it's a disease, and I don't think you can lightly say that someone has a disease unless they're openly telling you that they do."
By way of explaining her tiny frame so soon after giving birth to son Sparrow James Midnight Madden last September, she offers: "I'm nursing and he's a big boy, so..."
Richie also tells Marie Claire that she's got more on her plate than just her fashion ventures, revealing she's interested in launching a music career, writing another book (her 2006 book "The Truth About Diamonds" was a The New York Times bestseller), and starring as a young woman balancing work and home life in a television sitcom she's developing for ABC.
"I think that ten years ago someone would probably have said I was crazy to want so many occupations," she tells the magazine. "But artists like Beyoncé have paved the way, going from music to acting to designer, and I have a ton of respect for people like that."
To hear more about Richie's career plans and see more of her sultry Marie Claire shoot, head over to MarieClaire.co.uk and pick up the new March issue of the magazine on newsstands now.
For another celeb cover (or three), see which Jonas Brother got his fashion on.