Kelly Clarkson's marriage was ended by lockdown.

The 'Since U Been Gone' hitmaker has reportedly filed for divorce from Brandon Blackstock, with an insider claiming that being in isolation due to the coronavirus pandemic resulted in the pair of them ending their romance together.

A source said: ''Those closest to them know it's been difficult. Kelly and Brandon had been having problems for several months and were making a conscious effort to work things out. They both hoped quarantining away from L.A. in Montana would help them work things out in their marriage, but instead the change in environment was actually detrimental ... The constant time together seemed to make an already challenging situation worse. Her career definitely helped to keep her mind off things, but this recent downtime gave her the time she needed to think about her life and her marriage.''

And the 38-year-old singer decided to file the papers because she finally realised it was her ''only option''.

The insider added: ''Kelly knew she just needed to follow her heart and finally realised divorce was her only option.''

Kelly and Brandon's focus will be their children - River Rose, six, and Remington Alexander, four.

The source told Entertainment Tonight: ''Kelly and Brandon haven't cut each other off; they are still talking to one another. They are both heartbroken, but their plan is to put the kids first. Their focus is on co-parenting and moving forward, as this is the last place they ever thought they would be. They both understand divorce is never easy for children, but Kelly and Brandon are great parents. It'll just take time.''