Country star Blake Shelton is glad he filed divorce papers in Oklahoma because his split from wife Miranda Lambert was finalised before word of the big break-up leaked to the press.

The singers stunned fans in July (15) when they announced the end of their four-year marriage on the same day they became legally single again.

Now Shelton has opened up about the shock divorce for the first time, admitting their prenuptial agreement cut out any unnecessary drama.

During a radio interview on the Bobby Bones Show on Wednesday (23Sep15), the 39 year old said, "In Oklahoma, it happens so fast. Like, Miranda and I didn't have any kids, and we had a prenuptial agreement... Once we filed for divorce, it was over in, like, I think it was, like, a nine or 10-day waiting period until it's over."

He continued, "We knew if rumblings and rumours started coming out, they would just be that. By the time anybody knew anything, it was over... It was done."

The stars agreed Shelton would keep his Oklahoma ranch, which the couple had used as its marital home, while Lambert received the keys to their retreat in Nashville, Tennessee.

Shelton explained, "Our whole thing was, 'We are going to be cool about this, it is what it is. We're buddies'."

The former couple had been together for six years before tying the knot in 2011.