Merle Haggard, Carrie Underwood, and Florida Georgia Line are among the first confirmed stars for this year's post-ACM Awards concert special. 

Lady Antebellum, The Band Perry, and George Strait are also on board for the show, while more artists are expected to be added to the lineup. 

This year's Academy of Country Music event is honoring the men and women in uniform.  "ACM Presents: An All-Star Salute to the Troops" will be taped at the MGM Grand Garden Arena in Las Vegas on April 7th -- the day after the 49th annual ACM Awards.  The concert special will air on CBS on May 20th. 

Tickets for the show are available now through  The concert is supporting the Academy's charity, ACM Lifting Lives. 

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