When I Know What You Did Last Summer co-stars Freddie Prinze Jr. and Sarah Michelle Gellar started dating in 2000, they instantly became one of Hollywood's most beloved couples. The iconic duo have managed to stand the test of time, and Sarah celebrated the 20 year anniversary of their first date on Instagram earlier this month.

Her post revealed that she and Freddie may have never gotten together if it wasn't for a mutual friend's missed flight, and thanked that friend for inadvertently sparking their relationship. Freddie gave Us Weekly his own take on their epic romance this week, stating that he and Sarah are successful because they have no "false expectations" for each other.

The Couple's First Date Was A Twist Of Fate

Sarah and Freddie have been together for over two decades now, but Sarah revealed on Instagram that their first "date" was actually just an accident. The duo was supposed to meet a mutual friend for dinner, but after that friend missed her flight, they were forced to dine one-on-one.

Even though they'd already spent plenty of time together on the set of 1997's I Know What You Did Last Summer, it wasn't until this dinner that Freddie and Sarah finally fell for each other.

“Now 20 years together, 17 plus married and two kids, we still go to that restaurant for dinner," she wrote. "So thank you @sloaney77 for not showing up for dinner.”

Related: 15 Behind-The-Scenes Drama From 'Buffy The Vampire Slayer'

Freddie Explains Why Their Relationship Has Been Successful For Two Decades

In an interview with Us Weekly, Freddie said that he and Sarah are still going strong and gave some insight into why they've remained such a successful couple after over two decades.

“There’s no keys. There’s no rules. There’s nothing like that. I don’t believe in false expectations,” he explained. “I just believe in knowing who you are when you start a relationship. And if you don’t, then that relationship probably isn’t going to work.”

Freddie believes that people who pretend to be someone else while in a relationship can't live that lie forever and thinks it's unhealthy for one's significant other to "have a big hand in defining what kind of person you're going to be."

"So, knowing yourself is sort of the key to doing it.”

Freddie Wouldn't Have Picked Sarah Over Video Games, Though

Despite Freddie's love for his wife and mother of his two children, he admitted to Us Weekly that he wouldn't be with Sarah if she wouldn't let him play video games.

“I played video games since I was a little boy. Sarah knew I played video games. If she ever gave me a hard time about playing video games, Sarah and I would not be together," he said. "Period. There would be no us."

He doesn't think there's anything wrong with that, though, and he similarly allows Sarah to enjoy "trash reality television" despite his own distaste for it.

"If you love and respect someone, what brings them joy should make you happy, whether you’re involved with it or not."

Next: 20 Stunning Photos Of Buffy That'll Make Freddie Prinze Jr. Jealous