Adam Levine has enjoyed the 'longest love affair' with Blake Shelton

The Voice coach Adam Levine has been closer to Blake Shelton for much longer than the country singer's girlfriend Gwen Stefani.

The pair enjoy a close friendship on the NBC show, which has spilled over into real life, and even fellow coach Gwen, who is in a relationship with the country singer, admits to feeling a little jealous of the Maroon 5 frontman's bromance with her beau.

During a chat with People magazine ahead of the premiere of Season 12 of show which starts on Monday (27Feb17), Adam recalled his first meeting with the country singer.

“I remember when I saw him at the meeting at NBC, I was instantly very taken by him ’cause he was definitely not your typical country artist,” Adam told People magazine. “He was not a cookie-cutter guy, and the second we met, we were friends. All of the bulls**t that we do comes from a place of love.”

In turn Blake remembers his first encounter with Adam fondly. “It was this skinny guy with a white T-shirt with the collar all stretched out," he laughed. "I remember turning to my manager and saying, ‘I think that’s Adam Levine.'”

Blake has since formed a firm friendship with the 37-year-old, and calls him, "...one of the most loving people I’ve ever known."

“We drive each other nuts, but outside of this world, he’s one of my best friends and it’s because of his heart, " the Came Here to Forget singer shared. "He needs his face slapped around, but he has a huge, huge heart.”

Blake is the most successful judge in the show's history and his pick, Sundance Head, won the most recent season. He has recruited his pal Luke Bryan for the new season to help him mentor the wannabes. Alicia Keys rounds out the judging lineup.

Blake not only made a best friend on the hit show, he also got a new girlfriend after he and Gwen started dating more than a year ago. But Adam lays first claim to Blake,

“I’ve had the longest love affair with Blake out of everyone,” says the singer about working through 12 seasons with Blake.

“God, I wish I was you,” joked Gwen. “I made my best friend. I found my best friend!”