'I couldn't afford to fill up fuel': Keith Urban reveals he was broke when he heard his first song on the radio before becoming Australia's most successful country singers

He is one of Australia's most successful country singers.

And on Thursday, Keith Urban shared the story of the first time he heard his music on radio during an appearance on Nova's Fitzy & Wippa.

The 53-year-old revealed he was so broke at the beginning of his career, he couldn't afford to fill up fuel.

'Do you remember that feeling when you first heard your song being played on the radio?' host Ryan Fitzgerald asked.

'Yeah, [I was in] my piece of crap car, it was a Chev. It was horrible, always running out of petrol because I was barely keeping up with it. I couldn't afford to fill it up,' Keith said.

'I was about to run out of petrol and pulled into a petrol station and I'm putting petrol in the car and they had the speakers at the servo and I heard my song as I was pumping petrol into my rust bucket.'

In September, Keith credited his wife Nicole Kidman with aiding his music career by 'liberating' him.

Speaking to Stellar Magazine, the country singer said: 'I definitely married up. Isn't that what we're all supposed to be doing?'

Keith said that one of the surprising impacts Nicole has had is on his country music career is by broadening his taste in music.

'Nic's definitely had a big impact on my music in the last five to six years particularly,' he admitted.

'She had different musical tastes than I did when we met. It really liberated me a lot, introduced me to a lot of music I'd missed.'

'We also find huge common threads in the Aussie music we love, because we grew up at the same time.'

He also said the main change Nicole inspired is making him 'more fearless with my artistry... She's just very willing to try things; that's rubbed off on me.'