diff --git a/lib/moment-range.d.ts b/lib/moment-range.d.ts
index 1bc672f..5ca909c 100644
--- a/lib/moment-range.d.ts
+++ b/lib/moment-range.d.ts
@@ -5,7 +5,7 @@ export class DateRange {
   start: Moment;
   end: Moment;
 
-  constructor(start: Date | Moment, end: Date | Moment);
+  constructor(start: Date | Moment | null, end?: Date | Moment | null);
   constructor(range: [Date | Moment, Date | Moment]);
   constructor(range: string);
   constructor();
@@ -62,7 +62,7 @@ export class DateRange {
 }
 
 export interface MomentRangeStaticMethods {
-  range(start: Date | Moment, end: Date | Moment): DateRange;
+  range(start: Date | Moment | null, end?: Date | Moment | null): DateRange;
   range(range: [Date | Moment, Date | Moment]): DateRange;
   range(range: string): DateRange;
   range(): DateRange;