"Lost" is the first single from "The Hits," a CD of Hill's greatest hits scheduled for release later this year, CMT.com said Monday.
"When we heard the final playback of the song ... (everyone) knew that it was special," Hill said. "The timing couldn't be better for us to play something new for our fans."
In a preliminary event leading up to Tuesday's awards presentation, Gretchen Lewis jammed in old Las Vegas at the Fremont Street Experience with guests John Rich and Heart sisters Ann and Nancy Wilson.
The country singer's performance capped two days of free concerts and the fourth annual AMC Charity Motorcycle Ride, led by Montgomery Gentry. The motorcycle event raises money for the ACM Charitable Fund.
CBS will broadcast the ACM Awards live from the MGM Grand.