The American lead singer in the 'Need You Now' group - which also includes multi-instrumentalist Dave Haywood and lead and backing vocalist Charles Kelley - is planning to marry her drummer boyfriend Chris Tyrrell after he proposed in "exactly the way" she had always wanted.
The 25-year-old beauty told People magazine: "Chris proposed exactly the way I've always dreamed...
"Our families were close by, but it was just us out on a beautiful deck overlooking a lake in East Tennessee.
"We had just been on a hike and - in our workout clothes - he hit the knee! We feel so blessed by God that He sent us each other, and we are looking so forward to forever together."
Hillary's engagement to Chris - who plays for Love and Theft - was also confirmed on Lady Antebellum's twitter site, which featured the message: "It's official . Hillary is engaged!"
Hillary met Chris while touring with country legend Tim Mcgraw in 2010.