Williams, the granddaughter of music icon Hank Williams, told People magazine Coleman asked her to be his bride as they hunted for civil war relics in Leipers Fork last week.
She described the scenario as "a perfect engagement."
"I dug up a beautiful wooden box with my favorite love quote on it," Williams said. "And the engagement date carved in roman numerals. He wood-burned the letters onto the box! He got on one knee and I opened the box, underneath the flowers and basil were the rings."
The report did not say when or where the couple plans to wed.