Nicole Kidman has become vital to husband Keith Urban's music - he can't release a track if she's not a fan.

The Australian country star admits he has become dependant on what his wife thinks of a new song, and quietly watches her expression as she listens to whatever he is working on to gauge if it's any good or not.

"Nic, of course, hears everything over the course of about 15 months I've been working on... so she's heard everything over, and over, and over again," Keith tells Entertainment Tonight. "God bless her."

In fact, the actress was a big help to Keith as he picked the tracks for his new album Ripcord, which is scheduled for release in May (16).

"I'm interested in how I respond just when she's listening," he beams. "Without her saying anything, I have a particular response that's not necessarily the same without her. So, it's important. I need the girl view!"

And he admits many of the songs he writes these days are inspired by his wife: "All the love songs, I'm drawing from a particular place, (and) there's songs about being in the moment, about life, about reminiscing, songs about love, songs about love lost."

And, although Ripcord - Keith's eighth studio album - is only a couple of months from release, the singer reveals he still hasn't settled on a track list.

"That's actually becoming the hardest part of making the whole record, is deciding which songs go," he says. "I reach out to a lot of people I trust around me.

"At the end of the day, I have to make the decision, but I get a lot of people's opinions on songs because for me, every one of them is me. So when someone says, 'Well, just put the songs that are you', I'm like, 'Well, that's, like, a 24-song record'. I really gotta shrink it down."