Keith Urban appears to have thrown some subtle shade at his relationship with Nicole Kidman amid their shock split.

Weeks after the A-List couple confirmed that they had called it quits following 19 years of marriage, Keith is starring in the new CBS series, The Road, which sees 12 country music hopefuls vying to be the Grammy winner's opening act.

The series premiere, which aired in the US on Sunday, saw Keith take to the stage to perform his track Straight Line.

'Why we livin' every day in circles? Just burnin' out, burnin' out,' he sings on the track.

'I don't wanna just go through the motions. Goin' round and round. It's takin' us down.'

The choice of song may well have been a subtle nod to Keith's current marital woes, as he has previously revealed that the track is about 'breaking free' from 'soul-sucking' routines. 

Taking to Instagram in February last year, Keith shared a post promoting the track to his 2.8 million followers.

'Straight Line is wanting to break out of a soul-sucking routine that you might be stuck in,' he said.

'Maybe in a relationship, a job, with creativity, with yourself...whatever it is!! It's a message of feeling alive again and getting out from under that dark cloud.'

Elsewhere in the episode, Keith also revealed the eye-opening level of dedication required to spend extended periods away from loved ones.

'Where do we start?' he said, laying bare his thoughts on tour life.

'It's a calling, and you're going to do it or you're not going to make it.

'When you wake up on a tour bus at 3.30 in the morning and you're sick as a dog, you're in the middle of nowhere and you've got to play your fifth show later that night, and you haven't slept, and you miss your friends, and you're missing your family, and you're completely lonely and miserable and sick - and you say to yourself, "Why am I doing this?"

'The only answer can be: Because this is what I'm born to do.'

Turning his attention to the competition series, he said, 'We're going to find out who's made for that stuff.'

Keith's comments come just weeks after Kidman filed for divorce on September 30 after 19 years of marriage.

The former couple had been kept apart recently amid their hectic filming and touring schedules.

They share daughters Sunday Rose, 17, and Faith Margaret, 14.

The pair wed back in 2006 - five years after her split from actor Tom Cruise. Kidman and Urban had a traditional Catholic wedding ceremony at the Cardinal Cerretti Chapel in her hometown of Sydney, Australia.

One day after the news of their separation broke, Kidman officially filed for divorce and cited irreconcilable differences as the reason for the split.

According to the filing, the Moulin Rouge actress requested to be designated as the primary residential parent.

Sources also told the Daily Mail that Urban has reportedly moved on with an unnamed female musician.

Speculation had arisen that he could be linked to 25-year-old country star Maggie Baugh as well as singer Kelsea Ballerini, 32.

Nicole was reportedly left 'blindsided' by the separation.

A source stated, 'Keith never sees Nicole, either she is filming or he is on tour. 

'There was a lot of love between the two and they might not divorce, but there is a world that they both live where neither of them are in it.

'Keith and Nicole have been together for decades and there is a world which they can reconcile, but the way their pairing is now, it is not a couple.'