Freddie Prinze Jr. And Sarah Michelle Gellar's Hollywood Marriage Is 15 Years -- What's Their Secret?

Freddie Prinze Jr. and Sarah Michelle Gellar will celebrate their 15-year-marriage in September. As most people say, a relationship lasting this long in Hollywood is almost a miracle. So, what's this couple's secret?

Speaking exclusively with E! News, Prinze Jr. revealed starting off as friends with Gellar helped build a good foundation for their marriage. They had a platonic relationship for two years before they 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," the actor said. "We already kind of knew all the faults in the other person."

The actor advised single people looking to find their lifelong partner not to rush into getting married because it will surely end in divorce. "People think it's Hollywood that has so many divorces but it's a nationwide problem," Prinze Jr. told Mic. "My opinion is that people go too fast; they rush, they don't take their time and they get married for the wrong reasons."

#throwbackthursday and #thanksgiving all in one. This was our first Thanksgiving, and while we had a lot to be grateful for on that day, it doesn't compare to all that we have now. I try very hard to be grateful and appreciative all year, but it doesn't hurt to have one dedicated day. #grateful #happythanksgiving

A post shared by Sarah Michelle (@sarahmgellar) on Nov 24, 2016 at 8:11am PST

Prinze Jr. said he and his wife poured work over their 15-year-marriage. It didn't come with luck that they lasted this long and their marriage thrived despite all the pressures around their celebrity life.

Prinze Jr. and Gellar met and worked together in the movie "I Know What You Did Last Summer." Both were peaking in their respective careers as she was the star of iconic "Buffy the Vampire Slayer" and he was in league with other young Hollywood leading men like Phillippe and Paul Walker.

The couple has two kids, Charlotte Grace, 7, and Rocky James, 4. The dad said his children are the complete opposites as Charlotte is more conversant while Rocky takes a bit more prodding. "I have to give him a weapon in order for him to do anything!" Prinze Jr. said.

When his kids were born, the actor pretty much also became a full-time dad and together with his wife, they prepared meals for the family, which became a passion project. Prinze Jr. published his own cookbook, "Back To The Kitchen" and his wife has "Stirring Up Fun With Food."