Garth Brooks And Trisha Yearwood's Marriage Advice Is Worth Memorizing

It’s not exactly common to hear of couples who have been married for two decades or more — at least in Hollywood. But they’re out there, like bonafide country stars Garth Brooks and Trisha Yearwood, who have been married for 18 years.

When a couple seems to have the magic secret to a strong marriage, it’s understandable that people want to know what makes decades-long, successful relationships work. In a recent interview on Good Morning America, Brooks and Yearwood shared their best piece of marriage advice with host Robin Roberts before her wedding to Amber Laign. The video is honestly a hoot — a cute one if you can get past the endless flirting.

“We've been asked to tell you what we think the secret to a happy marriage is because we've been at it for almost 18 years," Yearwood says before a small, awkward pause as she looks to Brooks, sitting to her right.

"This is where you're supposed to say..." Brooks replied before the video went into a pause, and the two started over again.

On the second take, the couple plays off each other hilariously, with Yearwood joking that Brooks speaks for her now, while the two look at each other with pretended frustration.

"One of you has to be *** miserable," Brooks jokes. "That's right," Yearwood hits back. "And I am not happy." The two then bust into a giggle fit, clearly having fun pretending to give really bad advice.

"Never go to bed mad at each other," Brooks then says, with Yearbook rolling her eyes, saying: "What, did you Google that?"

Through even more giggles, the couple seems confused about why they were asked for advice in the first place. "Why are they asking us?" Brooks says to Yearwood as they both bust out in another fit of laughter.

After taking a moment to stop giggling, the two dropped the true secret they believe keeps them happy and in love after all this time, grab each other's hands, and together, they say the best marriage advice is "to marry your best friend."

The video is an adorable reveal at how playful and flirty these two still are after nearly 18 years together. And while we often hear that advice — marry your best friend — it’s because the statement is true.

"Friendship is a major part of a healthy, long-lasting relationship," Amy Morin, LCSW, a psychotherapist and author of the forthcoming book "13 Things Mentally Strong Couples Don't Do," tells Fatherly. "While intense romantic feelings may shift over time, friendship stands the test of time.”

Morin notes that when it comes to a long-term relationship, there needs to be a strong foundation. “Couples who truly enjoy one another's company will continue to spend time together and bond over the years, creating a deeper, more intimate relationship,” she explains.

However, Morin notes that feeling like you are best friends with your partner isn’t necessarily a make-or-break situation either. But couples who have that foundation of friendship do go a long way.

“If you and your partner aren't best friends at the moment, that's OK. You can always take steps to build and maintain an emotional connection,” she explains. “Think of it the same way you'd build a friendship with anyone else. Spend quality time together, be vulnerable, talk about deeper subjects that go beyond day-to-day stuff, and have fun together.”

You can watch the clip from Brooks and Yearwood on GMA.