Nicole Richie admittedly thought that The Simple Life would be a 30-day commitment.

"The concept of, 'Do I want to do reality television and what kind of space is it going to take up?'—no, it was all experimenting," the House of Harlow 1960 founder said on the podcast Second Life in 2019. "It was a new concept, and I was on board with it."

Little did Nicole know that she and childhood BFF Paris Hilton would be the toast of reality TV for five seasons. Or that to this day, cameras would still be following her everywhere.

"I get a lot of eyerolls, but I also get a lot of this, the phones sneaking up," the mom to daughter Harlow, 15, and son Sparrow, 13, told ET Canada in December, miming her kids surreptitiously angling their mobiles to capture her mom humor. "So I'm convinced that they're sending videos of me to their friends. Which I used to do to my dad all the time, and I thought he was embarrassing—but I also really thought that he was funny."

Which suggests that there's an assortment of Lionel Richie's other greatest hits out there somewhere. But in any case, this sort of playful spirit seems to rule at Nicole and husband Joel Madden's house.

As their 12th wedding anniversary approached last year, Nicole said she had no special secrets to offer for a lasting marriage, but she and the Good Charlotte rocker simply "let each other be ourselves and just have fun."

And though it was frequently two against one when it came to either of them dealing with Harlow and Sparrow—"teens can definitely gang up on you," Nicole noted—she's been enjoying this chapter of their lives.

"I like when people give it to me and show me a different side of myself," she said. "I think teens are going to be the fastest to show you a side that you probably have chosen to ignore about yourself. And I think they can be your biggest teachers, so I'm constantly learning from them." 

Which is basically how she and Joel approached parenthood from the beginning, both aware that there's nothing wrong with being confident but also be prepared for a lifetime of trial and error.

"You really can't plan anything, you don't know anything," Joel told People in 2009 when Nicole was pregnant with Sparrow. "You just have to take it as it comes...You have to have your own experience and learn as you go."

(He did rather adorably proclaim himself fit for the job a year later, though. "I'm not trying to sound cocky, but I'm a very good father—I'm an amazing father," he told Parade.com. "I'm not going to lie about that. In general, I'm pretty self-deprecating when it comes to my work or anything else. But when it comes to being a dad, I'm a great dad.")

Nicole echoed the sentiment a few years later. "There's no right or wrong way to raise a family," she told DuJour. "Look, I don't know anyone who can't say they don't just try and do the best that they can do."

If she and Joel sound very in tune with each other, that's just the way it's always been since mutual pal Samantha Ronson introduced the family-oriented pair in 2006.

In fact, when they first started dating they enjoyed "kind of playing house" with her then-8-year-old sister Sofia Richie, Nicole told ET Canada, reflecting that the now-24-year-old "wasn't our first kid, but she kinda was."

And then Nicole got pregnant with her and Joel's actual firstborn in 2007.

"We met and we were partners from day one," she recalled on Oprah: Where Are They Now? in 2014. "And from the second we found out we were going to be parents together, we looked at each other and we said, 'Okay, both of our parents are divorced. We both have had ups and downs with our parents and we don't really have a strong example of what a healthy family life is. But, we're recognizing that now, so let's work at it and let's go through this together as a team.'"

That was the plan and they're sticking to it.

Harlow was born Jan. 12, 2008, Sparrow arrived Sept. 9, 2009, and then Joel and Nicole tied the knot on Dec. 11, 2010. 

Recalling his eventual proposal, Joel said that he woke up one Tuesday and realized it was time. "I was just like, What am I doing?" he said on Australia's 60 Minutes. "I'm a fool, why haven't I asked her to marry me? And did it that night."

He and Nicole said their I-dos at her father's Beverly Hills home in front of guests including Gwen Stefani and then-husband Gavin Rossdale, Kris Jenner, Khloe Kardashian, Rachel Zoe, Ellen Pompeo and Pete Wentz, while Joel's twin Benji Madden stood by him as best man. (Joel returned the favor when Benji married Cameron Diaz in 2015.)

After respective early-'00s days of fame that resulted in enough tabloid headlines to last a lifetime, Joel and Nicole have since been enjoying their comparatively quiet life together ever since.

While they will amiably talk about the joys and challenges of parenting, they offer only rare pictorial glimpses into their family world, especially now that the kids are older. Not that they're averse to the occasional celebratory post, which is always a good excuse to share a baby pic.

"Here you are at 3 months old. Today you are 13," Nicole captioned her birthday post for Harlow in January 2021. "You light up my life with your presence, & have no problem lighting up my bedroom with your bright phone screen. Nothing is better than watching you become the young woman you are. I am so lucky I get to be your mom."

Though Harlow had long since officially entered mom's-twin territory, the multigenerational Mother's Day shot featuring her daughter, sister Sofia and mom Brenda Harvey-Richie that Nicole posted to Instagram Story May 14 showed off their stellar gene pool.

And while Joel celebrates his wife on Instagram regularly ("Our second trip down the aisle," he captioned a shot of them at Sofia's April nuptials in the South of France), he stuck to retro—albeit adorable—pics of Harlow and Sparrow to pay tribute to "one of the greatest of all time" on Mother's Day 2022.

Joel used the same tactic, incidentally, for his son's birthday in 2020, captioning a throwback pic of a much smaller Sparrow on his shoulders, "Happy 11th Birthday to my baby boy! I love you Sparrow... here's to many more years of being best friends and me embarrassing you."

But from what they have shared, the couple have been busy raising savvy kids who, yes, might gang up on them, but who also have a compelling argument when they do.

"I have to always come from a place of love and compassion with them," Nicole told Oprah Winfrey in 2014. "My kids operate best when I let them have a voice. And I really explain things to them, because really, kids want to be told the truth. They just do. They just want you to be truthful."

She continued, "I do know I do the best that I can. I'm probably constantly—every day—talking to other moms figuring out the best way to have a strong relationship with our kids."

Nicole emphasized early on that she planned to spend most of her time close to home for her kids' sake, remembering what it was like to grow up with a dad constantly traveling. But when given the option in 2016, the whole Madden-Richie family hit the road. 

"It's fun," Nicole told People of being on tour with Joel. "It's a very cool experience, especially for the kids." And even thought they were "waking up in a different city every day," she added, "they get to hang out with us all the time."

She described then-6-year-old Sparrow (who had already been putting on shows for the family for years) as Joel's mini-me—"My son likes to dress like his dad"—while 8-year-old Harlow was "a little more reserved" and sometimes preferred to just stay aboard their "awesome" tour bus doing art.

Considering Dad's a musician and Mom's a designer who named her jewelry (then sunglasses, bags, etc.) brand after her firstborn, Harlow being a creative kid certainly comes as no surprise. And the interest in fashion also came early, hence Nicole letting her daughter run amok—for the most part—in her closet. 

"My mom let me go through her closet," Nicole told E! News in 2016, "and she didn't treat her clothes like they were precious, so I do the same thing with her. There are times when she grabs something and I'm like [eek]...'Okay!' And then I sneak five minutes later and take it back." (And sometimes the borrowing ran both ways, as when Nicole stepped out in her daughter's on-point faux-furry pink jacket in 2014.)

And when she did a collab with Urban Decay in 2018, Nicole said her then 10-year-old also enjoyed experimenting with makeup. Maybe even more than her mom did.

Harlow's "a different beast than me," Nicole told People. "She should have this campaign. She is like a glitter, a liner, a liquid liner, a blush, a lipstick, a YouTube tutorial video. She is in it." 

In recent years, Nicole has said on multiple occasions that, with Harlow still shopping in her closet, she's taken to marking an "N" on all of her own stuff with a Sharpie to distinguish what's hers.

Joel has said that he hoped Harlow would turn out just like her mom—and not just because Nicole is so darn stylish.

Rather, she's "one of the strongest women I've ever met," he raved about his wife to Shane Power in 2018. "You cannot f--k with her. You can't f--k with Nicole, even if you think you are f--king with her. I've never met anyone on her level. She's just on a whole other level. I just hope that Harlow is like that."

Rest assured, that's always been Nicole's plan as well.

Noting that she had taken Harlow and some of her friends—at the kids' behest—to a Women's March in 2017, she explained that she wanted her daughter to always feel comfortable speaking up for herself.

"I want her to be able to look at any adult, male or female, for the rest of her life," Nicole told People, "and to be able to own how she feels and be able to tap into her instincts without ever feeling she has to protect anybody else or think about anybody other than her well-being and her safety. I want her to have power in her voice and confidence with her voice and her feelings."

However, when it comes to Harlow and Sparrow's own interests, any overlap with what their parents are into is totally up to them. 

Nicole said last year that she could see both of their kids "developing into themselves," but she was being careful not to deem either one of them "just like" her or their father.

"I have been really conscious to not say that around my kids," she told Entertainment Tonight. "My daughter loves fashion, but she's got her own style that doesn't have anything to do with me."

And should either Harlow or Sparrow come up to her and say, "'I want to try this new thing that hasn't been done before'"—well, first she'd say no because they're not old enough, she pointed out—"but if they're 18 and they want to go do whatever it is, as long as it feels good and authentic to them, I'm fine with it."

It'll just be one more new thing to learn about.

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