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.