diff --git a/chart.js/index.d.ts b/chart.js/index.d.ts
index 7a7b05c714..0830e68498 100644
--- a/chart.js/index.d.ts
+++ b/chart.js/index.d.ts
@@ -71,7 +71,7 @@ declare namespace Chart {
     }
 
     export interface ChartPoint {
-        x?: number;
+        x?: number | string | Date;
         y?: number;
     }
 
@@ -430,4 +430,4 @@ declare namespace Chart {
 }
 
 export = Chart;
-export as namespace Chart;
\ No newline at end of file
+export as namespace Chart;