Garth Brooks and Trisha Yearwood have discovered the secret behind their 15-year marriage, or what they described as "like 200 years in Hollywood."

The two country stars, who are guest hosting Friday’s episode of "The Ellen DeGeneres Show," revealed how they keep the spark alive – and it’s all about having a sense of humor.

The two tied the knot in 2005.

"I think you gotta treat it like a duet," Brooks told the audience. "You gotta harmonize, you gotta make your partner feel like they’re a star. And if not, you’re gonna turn into a solo act pretty damn quick if you know what I mean."

And the right soundtrack always does wonders for any occasion.

TRISHA YEARWOOD AND GARTH BROOKS ARE ‘EVEN CLOSER’ AFTER WORKING ON MARRIAGE DURING QUARANTINE

Trisha Yearwood and her husband Garth Brooks guest-hosted ‘The Ellen DeGeneres Show’ on Friday.

Trisha Yearwood and her husband Garth Brooks guest-hosted ‘The Ellen DeGeneres Show’ on Friday. (Michael Rozman/Warner Bros.)

"I think for me, music is the big thing to set the mood," Brooks told the audience. "And I don’t know if you listen to country music, but one of the greatest female voices ever on the planet is this gorgeous blonde named Trisha Yearwood. That’ll get you in the mood right there."

"You do need the right music, and there is this very sexy singer-songwriter guy who always gets me in the mood," Yearwood chimed. "Maybe you’ve heard of him, his name is John Legend."

However, life in the Brooks-Yearwood household isn’t always as smooth as a fine tune. Yearwood revealed that Brooks drives her crazy with his constant whistling.  

"Every significant other has at least one annoying habit even if you are in the perfect relationship, and you have to find a creative way to deal with it," said Yearwood, 56. "He actually told me to stop telling him not to whistle because it takes away his joy."

The 59-year-old particularly has a habit of whistling the theme to "Gilligan’s Island."

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Trisha Yearwood and Garth Brooks detailed what their marriage is really like to audiences.

Trisha Yearwood and Garth Brooks detailed what their marriage is really like to audiences. (Michael Rozman/Warner Bros.)

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"… After about three or four hours of whistling the same song over and over again, I do this thing where I change the tune," she said. "So I’ll start singing something else to kind of get him off track, and he doesn’t know it until now he knows it."

"Sneaky," said Brooks. "Really?"

The two even broke into a song that gave some sound advice on making any marriage work.

"Never go to bed angry, it ain't worth the fight/If you're wise you will compromise, and hold each other tight/Better learn to say yes, dear, every day and night/Only one thing to remember, the wife is always right," Brooks sang.

"He may drive you crazy, with the whistlin' he does/And after years of training, he ain't much better than he was/If you want to have marriage, well let me shed some light/There's only one thing to remember, the wife is always right," Yearwood chimed.