Morgan was performing Thursday for U.S. troops at Fort Bragg, N.C., when he received the invitation from Opry veteran John Conlee who surprised him by walking on stage.
Morgan, 44, was stationed at Fort Bragg from 1990 to 1992 during his 10 years of active duty in the Army's 82nd Airborne Division.
"It's cool to be invited right here," he said tearfully.
Morgan will be formally inducted as a member of the long-running country music program on Oct. 25.
Opry General Manager Pete Fisher said Morgan consistently shows a high degree of quality and integrity in his work, whether it's music or military service.
Morgan's hits include "That's What I Love About Sunday," "Redneck Yacht Club," "Little Bit of Life" and "International Harvester."
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(E! Online)