Charlie Daniels has announced the addition of Wynonna Judd and Terri Clark to the lineup for his 40th Anniversary Volunteer Jam.

Clark and Judd are joining a packed lineup filled with some of country music's biggest acts, including Trace Adkins, Alabama, Montgomery Gentry, the Oak Ridge Boys, Tracy Lawrence, Travis Tritt, Craig Morgan, Phil Vassar, Lee Greenwood, Billy Ray Cyrus, Colt Ford, Michael W. Smith, the Grascals, the Kentucky Headhunters, Ted Nugent, Ryan Weaver, the Outlaws and Lee Roy Parnell. Daniels has also hinted that fans can expect a few surprise guests at the 2015 event.

The 2015 Volunteer Jam, which is set to take place at Nashville's Bridgestone Arena on Aug. 12, will benefit the Predators Foundation (the official non-profit organization of the NHL's Nashville Predators) and the Journey Home Project, which aids U.S. veterans in need.

“It’s really something to see my music peers and friends come together this year to perform with little incentive other than to help raise funding and give back to those who have served," Daniels says of the event. "Few sacrifices are greater than those of our U.S. military, so it makes me proud to have witnessed this event come together in such a big way in 2015. We as U.S. citizens can never repay military members and veterans for what they have [done] and continue to do for us, but I hope at least this concert can serve a small role in showing them our great appreciation.”

Daniels began hosting the Volunteer Jam in 1974, and in 2013, he co-founded the Journey Home Project with longtime manager David Corlew. The organization works to serve as a connection between donors and veterans' organizations with proven records of helping vets with issues surrounding healthcare, education and post-military careers. More information can be found at TheJourneyHomeProject.org.

The 40th Anniversary Volunteer Jam will also feature a free-to-the-public pre-show, which is scheduled to run 4PM-7PM and feature Natalie Stovall & the Drive, the Grascals, American Hitmen, Jason D. Williams, Jesse & Noah Bellamy, Ryan Weaver, the Tucker Yochim Band, the Scooter Brown Band and the Justin McCorkle Band.

Ticket information for this year's Volunteer Jam can be found at Ticketmaster.com. Ticket prices start at $17.68.

Find out more about the 2015 Volunteer Jam here.

Country Stars Who Have Served in the Military