They'll be a big country wedding soon, just don't ask when. Country singer Vince Gill, 42, and gospel-pop star Amy Grant, 39, are engaged, Gill's spokesman, Erin Morris, confirmed in Nashville Thursday. "Other than that, they'd like to protect their privacy," said Morris. Grant, who is considered the biggest name in contemporary Christian music (her pop hits include "Baby, Baby" and "That's What Love is For") divorced Christian singer Gary Chapman last June. Gill, one of country's biggest stars ("Go Rest High on That Mountain" and "I Still Believe in You") got a divorce from singer Janis Gill in 1997.