Have you ever THOUGHT you understood the meaning of a song...until you read the lyrics and realized you were way off? That's what happened to Blake Shelton when he was IN the studio with The Doobie Brothers.

They were working on "Listen to the Music" for the Doobie's country duets album. Blake tells "People", "We were recording the song and I'm looking at the lyric going, 'I didn't realize that's what you were saying.'

"[They go], 'Yeah, this is like a statement on world leaders, if they can all get together and hang out together.' It's like, 'What? I just thought it was about whistling while you work or something!'"

The album, which is titled "Southbound", is out November 4th. Other performers include Toby Keith, Brad Paisley, Chris Young, Hunter Hayes and Zac Brown. You can check out a behind-the-scenes clip at Billboard.com.