diff --git a/os/gtime/gtime_time.go b/os/gtime/gtime_time.go
index 1730092c8..0854968ed 100644
--- a/os/gtime/gtime_time.go
+++ b/os/gtime/gtime_time.go
@@ -446,7 +446,7 @@ func (t *Time) EndOfYear() *Time {
 }
 
 // MarshalJSON implements the interface MarshalJSON for json.Marshal.
-func (t *Time) MarshalJSON() ([]byte, error) {
+func (t Time) MarshalJSON() ([]byte, error) {
 	return []byte(`"` + t.String() + `"`), nil
 }