(Darren Tieste)

When the public first met Kelly Osbourne on her family’s reality show “The Osbournes” in 2002, she was — in her own words — “a f—ed-up ugly duckling” teased mercilessly as “worthless celebrity spawn.” Fast-forward more than a decade (and more than a few mishaps, she’s quick to note), and she’s emerged a lavender-haired swan, with stints on “Fashion Police” and “Project Runway: Junior,” and her own fashion and makeup lines.

And now everyone wants to know how she did it. “People don’t pick up on your journey until you’ve arrived at your destination,” says Osbourne, 32, whose book “There Is No F*cking Secret: Letters From a Badass Bitch” will be released on Tuesday, a day before her talk with Kelly Cutrone at Sixth & I. “It’s committing to a life change, and it’s a lot easier said than done.”

The book is a series of smart, profanity-laden letters from Osbourne — to her parents, to her body, to addiction, to bathroom “seat sprinklers.” She spent more than three years on the book and now that it’s time to share it, she’s terrified people won’t like it. “I put everything into it, I bared my soul,” she says. “But it’s made me so very vulnerable.” Express talked to Osbourne about fashion, recovery and the misconceptions she wants to shatter.

Kelly Osbourne book Kelly Osbourne’s new book comes out Tuesday.

Why did you write this book?
There’s this weird delusion that when you’re famous, you don’t have problems. It’s such the opposite, and I want people to know they’re not alone, that there are other people who go through what they go through and know what it feels like to not want to get out of bed in the morning. I want people to read this and have the courage to start liking themselves, because to not like yourself — or to wish you were someone else — is one of the worst things in the world.

You write candidly about your drug addiction and rehabilitation. Is it something you continue to work on?
Yes, I’m in therapy. I believe if you’re not in therapy, you’re crazy, because everybody needs a nonbiased perspective into their lives and someone they can talk to.

Just last night, I was at dinner and somebody brought a friend none of us really knew. And he was asking every single person, do you want to get some [cocaine]? I was sitting there nervously and uncomfortably, and finally I was like, ‘no.’ But then I looked at the positive of it — that I actually don’t want to, and it’s not a part of my world anymore. People have this idea that you do drugs for fun, but I did drugs to numb myself because I hated myself and my life.

Requisite fashion question: What’s about to be big, and what will soon be out of style?
It’s going to be a lot of high-end looks that women wear with sneakers — even Victoria Beckham isn’t wearing the high heels she used to wear every day; she was just wearing a pair of chocolate Adidas with a beautiful black suit. Power suits are coming back for women, and I really hope the ombre and gladiator shoes are going. They didn’t look good on gladiators, so why the f— are you still trying to wear them?

Sixth and I, 600 I St. NW; Wed., 7:30 p.m., $17