Rascal Flatts, George Strait, Garth Brooks and Merle Haggard are also in the ACM Awards record book.
Women account for three of the five nominees for album of the year.
Parton & Brooks tell Billboard what they are most excited about in pairing for the May 11 show.
The event will be held the day before the 58th annual ACM Awards.
The key changes are in album of the year and songwriter of the year.
