diff --git a/moment-timezone/moment-timezone-tests.ts b/moment-timezone/moment-timezone-tests.ts
index 410c45fe2e..5ce57818c1 100644
--- a/moment-timezone/moment-timezone-tests.ts
+++ b/moment-timezone/moment-timezone-tests.ts
@@ -80,7 +80,7 @@ moment.tz.setDefault('America/Los_Angeles');
 
 moment.tz.guess();
 
-moment.tz('America/Los_Angeles').zoneAbbr();
+var zoneAbbr: string = moment.tz('America/Los_Angeles').zoneAbbr();
 
-moment.tz('America/Los_Angeles').zoneName();
+var zoneName: string = moment.tz('America/Los_Angeles').zoneName();
 
diff --git a/moment-timezone/moment-timezone.d.ts b/moment-timezone/moment-timezone.d.ts
index c1d7e2d23f..870f0d6309 100644
--- a/moment-timezone/moment-timezone.d.ts
+++ b/moment-timezone/moment-timezone.d.ts
@@ -9,8 +9,8 @@ declare namespace moment {
     interface Moment {
         tz(): string;
         tz(timezone: string): Moment;
-        zoneAbbr() :Moment;
-        zoneName() :Moment;
+        zoneAbbr(): string;
+        zoneName(): string;
     }
 
     interface MomentStatic {