Miranda Lambert has ''calmed down'' now she has turned 30.

The country singer - who is married to Blake Shelton - admits she no longer has what she describes as her ''I'll burn your house down if you don't listen to me'' attitude and feels much more ''settled'' and happy.

She said: ''That attitude brought me here and got me where I am. But that was me in my 20s. The chip on my shoulder is gone.

''At some point, you calm down. I'm happy. I'm more settled. I've put down roots.''

However, Miranda insists she didn't feel she had to change for other people.

She said: ''I feel like people have accepted me for who I am, with all the craziness, loudness and fire.''

The 'Automatic' singer admits it is hard to hear speculation about the state of her marriage, but she thinks country music stars tend to have more solid unions than other people in the public eye.

Speaking to People Country magazine, she said: ''There were rumours that it was about our marriage, that it had become boring and predictable. How do people even think that up?

''It's not easy when everyone is trying to tear you down, but you make a commitment and you stick to it. In other parts of the entertainment world, it sometimes seems like marriage is so disposable. But country has some enduring marriages - Johnny and June, George and Nancy, Faith and Tim. I'm thankful we have those role models. I feel like our peers are rooting for us. They're holding us up.''