For the more traditional among us, brass is considered to be the classic 21st anniversary present. So now that Sarah Michelle Gellar and Freddie Prinze Jr. have hit that particular milestone Sept. 1, they might consider shipping off a piece of heavy metal to their good friend. 

Because had their mutual pal not missed her flight to the west coast on that fateful January 2000 day, the I Know What You Did Last Summer costars may have just carried on indefinitely as buddies who have the occasional friendly meal. 

Instead, with their dinner companion a no-show, "we decided to still meet and catch up," Gellar shared on Instagram. 

And at upscale sushi eatery Asanebo, Gellar did something that left Prinze floored. "A lot of girls back then in Hollywood—as far as the actresses—they didn't eat. They ate salad," the onetime aspiring chef recalled in a 2016 Facebook Live interview. "Sarah came to dinner with me, and we sat down. She ate everything, including a crab that they let walk across the counter, then killed while it was alive in some oil and said, 'It's popcorn, try.'" 

As she popped the crustacean in her mouth, everything kind of clicked: "I was like, 'Yo, my girl is legit.'"

The spot still stands as Prinze's favorite ("They got a five-star Michelin rating, and its Zagat guide food review is one word. It just says 'Perfection,'" he told E! News), just as Gellar remains "his" girl, more than two decades and two kids later. 

An actually eternity in the Hollywood relationship landscape, it's even more impressive when you consider Gellar and Prinze were just 22 and 23 the night their friendship suddenly became something more; 25 and 26 when they wed in Mexico two-and-a-half years later. 

Celebrity couples who sail past that seven-year mark with nary an itch tend to get quizzed ad nauseam about the secrets to their success. So the actors have attempted to explain their lightening in a bottle a time or two. They put in the work, as she told Us Weekly, stressing that "to have a successful relationship, whether it's marriage, whether it's friendship, whether it's business, you have to put the time, if you want to see the results."

And, yet, "we know when someone needs a little space and we know when someone needs a hug and when someone needs a laugh," she explained to E! News in February, detailing Prinze's recent practical joke that made her laugh until she cried. 

But mostly, she and the Punky Brewster actor, 47, just like each other, an entirely underrated factor when it comes to long-lasting unions. "I think it's great to be in love," Gellar, 46, told Steve Harvey, "but it's also nice to like each other and like spending time together."

That part of their relationship clicked early on, the pair connecting on the I Know What You Did Last Summer set some three years before that unexpected first date. 

Though they shared few scenes in the North Carolina-set instant horror classic, they spent a great deal of time together. A native New Yorker, Gellar "didn't have a driver's license," Prinze explained to Us Weekly of the 20-year-old. Which was a problem when shooting took place in the coastal town of Southport, 30 miles from the nearest big city of Wilmington.

"It was an hour drive just to get to the gym," he continued. "So, I started driving her, and that's when her and I became friends. And we just would talk about life and stuff like that, and we had completely different philosophies on just about everything. 'Cause she was a born and raised New Yorker and I was a born and raised L.A. kid, and we just looked at everything like night and day."

By the time they wrapped, "I just wanted to be friends with her because I thought she was too skinny and I wanted to cook for her. Because that's what my family does," the future Back to the Kitchen author said of Gellar, then in the first season of her fame-making, butt-kicking gig as the titular Buffy the Vampire Slayer. "And so, we started this weekly barbecue thing at her house, and me and my cousins would come over and cook food for her and her friends. And then we'd make sure everybody ate, and that was kind of how our friendship began."

In the years that followed, they'd get together as often as anyone might see a past coworker, Gellar telling People, "We were friends for a very long time. We've had many dinners before." (And a set visit or two, Gellar making the briefest of non-verbal cameos in 1999's She's All That because she was there hanging out with Prinze. "I think you really understood that my character did not want pepper," she joked on Instagram of the cafeteria moment.)

But there was something about that night at that spot, with Gellar's adventurous palate impressing confessed Japanophile Prinze. "We were just two people at dinner catching up," she continued of their unexpected date night. "We had a long car ride and a long dinner, and things just happened."

A friendship already solidified, they both knew pretty quick that this could be it, their connection extending far deeper than their early 2000s pop culture dominance and the fact that they're both really, really ridiculously good-looking. (Though, that doesn't hurt, Gellar joking to E! News in 2013, "He's a good looking man. I'm not gonna complain!")

Being able to fast-forward past the getting-to-know-you bit was "one of the reasons I think our relationship has always been so good," Prinze explained to E! News in 2017. "We were just friends for a good two years before we ever went on a date. She knew what kind of guy I was. She knew what my morals were, what my priorities were and vice versa. We already kind of knew all the faults in the other person." 

Perhaps more importantly, they knew each other's good qualities, the ones that pointed to this being a particularly auspicious match. 

"Sarah and I are always very direct and blunt. That's how we've rolled for 20-plus years," Prinze told Parade.com. "If I do something that'll make her mad she's like, 'Hey man that sucks, why'd you do that?' Then I'm like, 'Oh god, I'm sorry,' and I don't do it again."

He much prefers her brand of candor over any sort of passive-aggressive behavior. "She'll let you know how she feels for better or worse," Prinze continued. "That's why Sarah and I are still together, cause there are not many girls like her out there."

Because from the moment they crossed that just friends boundary, "I didn't go on dates with other girls nor did I even want to pursue dates with other girls," he told People. And despite each having declared they didn't believe in marriage, "one day, I just knew we're going to get married and that I was going to propose. I didn't know when or how."

Fortunately, when he got down on one knee in April 2001, he continued, "she was on the same page and my instincts were correct."

A hurricane threatened their Sept. 1, 2002 vows near Puerto Vallarta, giving credence to that whole rain-on-your-wedding-day-is-good-luck adage. But after a rehearsal dinner that had guests such as Wilmer Valderrama, Dulé Hill and Gellar's bestie Shannen Doherty partying at the pool until 3 a.m., planners simply moved the Adam Shankman-officiated ceremony indoors and the show went on. 

Back in Los Angeles, their careers surged ahead as well, Prinze capping off his teen flick reign playing the Fred to Gellar's Daphne in two live action Scooby Doo films before pivoting onto television. And having staked her final vampire in 2003, the former All My Children bad girl booked a slew of films, including 2004's The Grudge, a thriller that took her to Japan where she picked up what Prinze recently called "my favorite gift ever." (A Katana blade from a master swordsmith, "She had to get actual paperwork from the government.") 

But their biggest presents came seven years into their marriage, daughter Charlotte arriving in September 2009; son Rocky three years later. 

Prinze's own dad having died by suicide when he was 10 months old, "for me being a father, not having a dad, it makes it my No. 1 priority," he stressed to E! News in 2017. "So when my daughter was born, that was pretty much it for me. I became a full-time father. It's not a job. It's what I love to do."

A season-long stint on 24 wrapped, he became very choosy about his next projects. "We fight over who gets to stay home," Gellar, herself raised by a single mother, admitted to Us Weekly in 2012. "You'd think it would be the opposite, that the parents would be like, 'No, I'll go to work!' but he's like, 'You stayed home for two years! It's my turn!'"

Having returned to work, first on Ringer, then with Robin Williams in The Crazy Ones, Gellar arranged her hours so that she was able to be home for wake-ups or bedtimes. And in 2015 she launched the passion project that's afforded her a bit more flexibility, her low-sugar, organic baking company Foodstirs the sweetest of success stories. 

Back on screens these year with Wolf Pack, a project she also executive produced, Gellar knows she's had more than her share of wins. "I have accomplished more in my career than I think I could have ever anticipated," she told W in 2019. "I've been a product of not one but multiple shows that resonate, that people still watch, that people still love and talk about. So, for me, it's all gravy."

Though Gellar's proud "that I've been able to use storytelling to make a difference in people's lives," her kids bring her the most gratification, hands down. They're the people in her life who can appreciate that she literally slayed on television, but still care more that she helps them bake cookies and achieve cool hairdos. "I try to separate myself as much as I can," she told W. "I always say, there's Sarah Michelle Gellar and there's Sarah Prinze. And they're two different people."

Sarah Prinze shares homework and cleaning duties with her husband who just so happens to also be an early aughts icon. She worries about how her kids will fare at sleepovers ("I wanted to spend the night downstairs in their guest room, but I sort of got kicked out," she joked to Momtastic in 2015) and tries to best the geniuses that turn up to compete each weeknight on Jeopardy.

"We work as a team, so any point I get, she gets, any point she gets, I get," Prinze explained to Parade. "The last one that we watched, we got the first six answers in a row. We were like, 'are you kidding me right now?! Time for someone to be on Celebrity Jeopardy!' But we didn't get any right for the rest of the show."

They sure have figured out the answer to keep a marriage humming along two decades in, though. 

They're not big on Valentine's Day ("We don't do presents, but we'll get some smooches in there man," Prinze told Parade), prefer "date nights at home where I'm cooking," said Prinze to fancy outings and they are serious when it comes to dedicated family time. 

"When I had kids, I sort of reevaluated my life," Gellar reflected to POPSUGAR in 2017. "You realize our society is such a technologically savvy and advanced community, but what are those moments where you really connect? Where you put the phones down and you really have that one-on-one moment. I had this epiphany and I realized everything in my life was around food. Whether that's having dinner at your home in the kitchen or you're hanging out with friends, those are where the memories happen."

So they make them count, committing to regular family dinners with few distractions. "Some people say our expectations are a little higher than most," she admitted to Us Weekly in February 2020. "We have no phones at the table. We sit, we all have dinner together."

After all, they know just how important one seemingly insignificant meal can turn out to be. 

"We ended up being the perfect balance," Prinze told E! News of their friends-to-forever journey. "There was a solid foundation built, and that's probably the main reason why we've always been cool and groovy." 

This story was originally published on Monday, March 8, 2021 at 12 a.m. PT.