Camila Cabello now knows how her "The Voice" co-judges Blake Shelton and Gwen Stefani are still in love even after being together so many years. The singer says she has learned about the "key" to their romance.

"They're so adorable. I asked them, 'What is the key? You know you guys have been together...' cause they're so happy and in love...it's so real," Cabello said Tuesday during her appearance on "The Drew Barrymore Show."

The 25-year-old singer further shared that the couple are not "making out, but they're cuddly with each other and they're like obsessed with each other." She went on to disclose what the couple told her about their romantic relationship.

"What they say about their key to like being so happy is that they're best friends and they make each other laugh, like they're laughing all the time," Cabello said. "That's like something that's really important for me."

Cabello also asked Barrymore, who doesn't shy away from giving relationship advice, what was important for her in a relationship.

"Probably the most important quality: Emotionally stable and funny," Barrymore replied. "Those are my two favorite things. Again, hard to figure out on a dating app if they're either."

The "Havana" singer immediately shared her own dating app experience, revealing that she left a dating app after 24 hours.

When Barrymore asked, "Why did it make you run away?" the singer explained the first guy who messaged her was an "aspiring singer-songwriter from Nashville" and she felt weird because somebody could be using her. "Does that make sense?" Cabello asked Barrymore, who replied, "You don't know their intentions."

"Yeah, you don't know their intentions," Cabello added. "But even that, I'm like I don't even know, when you are just trying to make friends, you're going to meet guys that are vetted by your friends, which is amazing."

Cabello was previously dating Canadian singer Shawn Mendes. The couple called it quits last year after being together for almost two years.

Stefani and Shelton celebrated their two-year engagement anniversary Tuesday with a PDA-filled photo.

Stefani shared a throwback picture of them kissing. She flaunted her engagement ring and captioned the post, "2 years ago today." The couple got married in July last year after dating since 2015.

The Voice
Pictured [L-R]: Blake Shelton, Gwen Stefani, Camila Cabello, and John Legend will be judges on “The Voice” Season 22. Vijat Mohindra/NBC