diff --git a/format/format.go b/format/format.go
index 0dac3bf4a..a9d265136 100644
--- a/format/format.go
+++ b/format/format.go
@@ -255,7 +255,7 @@ func formatValue(value reflect.Value, indentation uint) string {
 	case reflect.Map:
 		return formatMap(value, indentation)
 	case reflect.Struct:
-		if value.Type() == timeType {
+		if value.Type() == timeType && value.CanInterface() {
 			t, _ := value.Interface().(time.Time)
 			return t.Format(time.RFC3339Nano)
 		}