If it was fame Nicole Richie wanted, she sure got it -- just by being herself. She and pal Paris Hilton played themselves: two spoiled rich kids slumming alongside regular folk in the hit show, "the simple life."
On the show, and in real life, Richie was the wild one -- fresh from rehab, she delighted the tabloids with her fashion faux pas.
The wealthy socialites' wild antics on the show, as they discovered how working class Americans live, made them famous, richer -- and enemies. After taping the third season, it was widely known that the two best friends had had a falling out.
Richie told "20/20" the rift isn't tied to a specific incident or rivalry or the rumor, which she denies, that she showed Hilton's infamous sex tape to friends when Hilton was asked to host "Saturday Night Live" without her.
"Do you know, there is nothing that really happened. We have just grown apart. And, you know, we are just no longer friends," she said.
But People magazine's executive editor, Peter Castro, said money started the now-famous feud between the two starlets. "Nicole felt that she was bringing as much to the table in, in 'the simple life' as Paris was. So why is Paris making $5 million a year and not me?" he said.
Castro doesn't think it's just a matter of friends growing apart. "I think they're the Gen Y version of Jerry Lewis and Dean Martin -- these great, great friends who had this incredible success together, this professional relationship and then essentially overnight they hated each other. And I think a lot had to do with rivalry and jealousy on both ends," Castro said.
Richie dismissed the speculation about their friendship's demise, saying, "The rumors just fuel controversy. I am sure it stirs up controversy -- which I am sure she loves -- but, you know, I really have nothing bad to say," she told "20/20."
Despite their falling-out and an earlier announcement that Fox Television was canceling the show, the pair is set to continue production on the fourth season of "the simple life."
Whether "the simple life" endures for another season or not, Richie seems to be firmly established as an A-list celebrity.
She's a regular on magazine covers. She's appearing in the new film "Kids in America." She's working on an album. She's written a novel. And she announced her engagement to Los Angeles disc jockey Adam Goldstein, also known as DJ AM.
Richie's book, "The Truth About Diamonds," parallels her own life. It's the story of the daughter of a hot music star, who lands a TV show and finds happiness after a well-publicized drug addiction.
Adopted by music superstar Lionel Richie and his then-wife Brenda, Richie grew up in the lap of luxury. But she remembers seeing little of her famous father.
"I would always beg my Dad not to go to work, because work for him meant that he would be gone for months at a time, because I grew up in the '80s, and that was the pinnacle of his career. So him going to work was, was hard," she said.
And things got even more difficult. When she was 9, her parents went through a bitter separation after her father had an affair with another woman.
In her novel, Richie's main character begins using drugs as an escape. And she acknowledges that's something she understands.
She said her drug habit began very casually. "You know, pot at 13, which, in my circle, was very normal. … and drinking every once in a while, but that wasn't really my thing. And then I started getting into cocaine at like 14 or 15. And then I stopped. And, and went to heroin, at about 19, I believe," she said.
In retrospect, Richie said, "I was pretty out of control. And considering the fact that I probably don't remember half of what happened to me, I can only imagine how out of control I was."
Ironically, just days before she was scheduled to check into rehab for help, police found heroin in the car she was driving. "It kind of didn't make sense in my mind at the time. … This is the one time I am not doing anything wrong. But I think that it was kind of a sign. A little reminder of like, 'this stuff really happens to people,'" she said.
Richie completed rehab, was put on probation and began her new life with a hot TV show.
But Richie now had a weight problem. She had put on pounds in rehab, but then underwent a dramatic weight loss that led to speculation about her health and whether she had returned to drugs.
She said she's remained drug- and alcohol-free since leaving rehab. And she insists the weight loss was gradual and that she's simply dropped the extra weight with the help of a personal fitness trainer.
"I have been called too fat. I have been called too skinny. I have been called too short. I have been called wild. You know, I mean, I can't, I can't even keep up with the things that people say. So I just, I just don't. I choose not to," she said.
Still, as with her famous flap with Hilton, rumors persist. And Richie just tries to ignore them.
"I know the truth, and my family knows the truth, and my friends know the truth, and just like drugs, you know, if, if there was a problem, then I would step up to the plate and take care of whatever I needed to take care of, and that's the way that I live my life," she said.
Some credit Richie's turnaround to her romance with Goldstein. The couple announced their engagement in February.
He too is a recovering addict, finding a new life after losing 150 pounds through gastric-bypass surgery. "They had a common hardship and that is sort of the mortar of a lot of relationships. And they had a lot in common going in. He has really settled her down and I think it's sort of like the kind of serenity that she's never had before," said People's Castro.
It's hard to imagine the young socialite falling in love and settling down.
She said it's hard to describe how their friendship grew into love, but she says she's smitten. "If you spend five minutes with him, you'll know in a second. He's just that person. He's just very charming, and there's something about him that makes you fall in love with him," she said.
Richie said she's happy where she is now, and is glad to have pulled herself out of the downward spiral of drugs and rehab.
"I just consider myself really lucky that I got through everything. And I couldn't have done it alone, you know, I have my parents, and uh, a lot of great people around me, and I just feel very lucky."