Blake Shelton will be the first to admit his relationship with Gwen Stefani snuck up on him. After going through a divorce with Miranda Lambert, the artist says Stefani stepped into his life when he least expected it.

The now-couple first connected, Shelton says, because of their similar splits. The country singer explains that Stefani really empathized with him when he told his show mates about the breakup and later pulled him aside to talk to him alone.

"I thought it was going to be another one of those things-are-going-to-be-OK talks," he recalls in an interview with Billboard. "She didn't tell me much, because we didn't know each other at the time, but she said, 'I'm going through something very similar to what you're going through. I understand. And I hate it.’"

Shelton says from there, their relationship grew gradually until he realized he had feelings for her.

"That’s kind of how our friendship and bond started, that day. It went from that, to checking in on each other once a week through email — 'This sh-- happened to me, what happened to you?' — to maybe three times a week, then every day, to 'Hey, here's my phone number if you ever want to text.'"

Adds the star, "Next thing I know, I wake up and she's all I care about, and I'm wondering if she feels the same about me."

The unlikely pair has since grown even closer, writing songs both together and about one another, including a duet called “Go Ahead and Break My Heart,” which appears on Shelton’s latest album. He began writing the song to try to impress Stefani, but was quickly outdone by her songwriting prowess.

"She wrote a verse that was brutally honest and didn't really go with my verse. I was writing about her, and she made it about us. I was so taken aback by it. F---, she's awesome,” he says.

His record, If I’m Honest, is one of his most personal yet, and if you listen closely, you can hear traces of his divorce, Shelton says — even though he didn’t write many of the tunes. Stefani also wrote a very personal record called This Is What the Truth Feels Like in which she shares similar feelings.

Gwen Joins Blake Onstage for His Birthday

Blake Shelton's Most Unforgettable Moments

More From 101.5 KNUE