Congratulations to Blake & Miranda who got engaged this past weekend on May 9th!

"He called my dad and got his blessing first," Lambert tells PEOPLE about Shelton's surprise proposal on May 9. "That was so Southern and old-school and perfect."

Equally perfect: The diamond-and-platinum ring "Hillbilly Bone" singer Shelton, 33, chose on his own.

"I was so proud of him," says Lambert, 26. "We've been together five years, so he knew exactly what I wanted but it's so much more perfect than I could have picked out myself."

The setting for the proposal was distinctly down-home – in the woods near Lambert's Tishomingo, Okla., home. And the celebration was similarly informal: "We had a couple of Bacardi and Diet Sprites – in a Solo cup!"