The gals struck ratings gold in the process. The premiere episode drew 13 million viewers, and numbers only grew higher from there. Bonus episodes, a reunion special, and DVDs followed.
But the hit show was also the beginning of the end for the lifelong pals. Reports of feuding and rivalry—further complicated by tandem substance abuse issues—led to the show's demise in 2007.
Paris and Nicole seem to have since mended their relationship, but they'll never reignite the sparks that drew viewership in the mid-2000s. Let's take a look at their long history together.
Paris and Nicole are both heiresses to a hefty fortune (Hilton is the great-granddaughter of Conrad Hilton, the founder of Hilton Hotels, and Richie is the adopted daughter of singer/producer Lionel Richie), so it's no surprise that they formed an instant bond. The two grew up in the same exclusive Los Angeles neighborhood and even attended the same prestigious school (The Buckley School) as young children.
Whether they were playing dress-up as kids, causing trouble in Las Vegas at 13, or ruling the Hollywood club scene in their 20s, Paris and Nicole were rarely apart. In 2007, Richie told Harper's Bazaar that she definitely considered Hilton her partner in crime.
"When we were little, our parents always wanted to separate us," said Richie. "And I remember, word for word, them saying it's not that it's me and not that it's her. It was the two of us together."
"We were just like sisters from the moment we met," added Hilton.
In 2003, Paris and Nicole put their friendship in the national spotlight by starring in The Simple Life. The comedic reality show followed the two socialites as they attempted to make it in "the real world."
For the first season, they ditched the trappings of their luxurious lives—cell phone, credit cards, etc.—for a month on an Arkansas farm. The BFFs stuck together as they failed their way through jobs at a dairy farm, gas station food mart, taxidermist's shop, and more.
Ratings were so successful that Nicole and Paris took the second season on the road. For The Simple Life: Road Trip, the dynamic duo continued working various blue-collar jobs (catching crayfish, cleaning at a nudist resort) while discovering new concepts like paying tolls.
But things began to come undone after the third season (The Simple Life: Interns). In April 2005, Hilton shocked fans by announcing that her bestie would be replaced by another pop star's kin—Rod Stewart's daughter Kimberly—for Season 4.
Contrary to Hilton's claims, Richie continued with the show. The Simple Life moved from FOX to E!, debuting the fourth season in 2006. The fifth and final season, The Simple Life Goes to Camp aired in 2007 and closed the book on the pair's time as co-stars, but fans were always left wondering what really happened during their brief rift.
Don't hold your breath for a reboot, though.
"That concept wouldn't even work in this moment because, remember, we'd leave our lives for a month, and we didn't have any phones," Richie said in an interview with Entertainment Weekly. "No phones in this day and age just doesn't work!" She also said that the show wouldn't fit with her adult life as a mom and wife.
Paris agreed, tweeting, "I have an extremely busy work schedule traveling the world running my empire."
"It’s no big secret that Nicole and I are no longer friends," Hilton said in a statement published in People. "Nicole knows what she did, and that’s all I’m ever going to say about it."
Richie denied the incident. A source close to her told the magazine that "tensions arose because Nicole has grown out of her wild ways, quitting drinking and spending more time with her fiancé, Adam Goldstein."
“She just wants to be with Adam and get married,” said the insider.
But the rivalry created moments of tension over the next year. They attended the 2005 Vanity Fair Oscar party separately and ignored each other in the green room at that year's MTV Video Music Awards. When it came to partying at their favorite hotspots, like LA's Hyde nightclub, the two avoided one another.
After an awkward fourth season of The Simple Life, in which they shared very little screen time, the gals reconciled for the final season—but was it real or just for the cameras?
"I don't even know why we're fighting. I think it's just the tabloids," Paris said to Nicole in the season premiere. "I just want to let you know half the things that the tabloids said that I said were not true," Nicole replied.
With both women now approaching 40, enough time has passed to let go of the grudge.
Besides that one incident, the former besties have only spoken kindly of each other in interviews and TV appearances.
"Paris is somebody that's been in my life since day one," Nicole told Andy Cohen on a 2014 episode of Watch What Happens Live. "I haven’t spoken to her in a while technically, but, if you really want to get into it, my view of a friendship is someone that you don’t necessarily have to talk to you every day. It’s somebody that you can call when you need them, and they’re just going to be there. So, time as whether I’ve spoken to somebody is really… it doesn’t really matter in my opinion.”
"An idea of a true friend is somebody that's going to be there with you through and through ... I haven't spoken to her in a while, but we are very good friends. I love her and I love her family. I have a lot of respect for her."
Hilton returned the love in a 2016 interview with an Australian news outlet, saying, “[The Simple Life] was such an amazing time to be with my best friend, traveling around the world, doing all these crazy jobs."
“[Nicole] is literally the funniest person I’ve ever met in my whole life. She’s always cracking me up.”
Occasionally, one or the other will post a sweet sentiment or picture of them together on their social media accounts, like this Instagram birthday post where Paris said, "I will always think of you as a sister & think of you often. Love & miss you." Judging by the looks of it, the two have genuinely kissed and made up.