Ronnie Dunn, Rodney Atkins, Randy Houser and Jerrod Niemann have been added to the list of participants at the fifth annual ACM Honors program taking place Sept. 19 at the Ryman Auditorium in Nashville. Presented by the Academy of Country Music, the event celebrates the special honorees and non-televised category winners from the 46th annual ACM Awards held earlier this year in Las Vegas. Garth Brooks, Reba McEntire, Taylor Swift, Tom T. Hall and Larry Gatlin & the Gatlin Brothers are among those being honored. Brooks is not expected to attend. Joining Dunn among the presenters are broadcaster Ralph Emery, Laura Bell Bundy and John Michael Montgomery. In addition to Atkins, Houser and Niemann, newly-announced performers include Jack Ingram, Thompson Square, Lee Ann Womack, the Isaacs, the Whites and songwriter Dean Dillon.