diff --git a/types/vis/index.d.ts b/types/vis/index.d.ts
index 813a149baf..80be24f8b0 100644
--- a/types/vis/index.d.ts
+++ b/types/vis/index.d.ts
@@ -193,8 +193,8 @@ export interface TimelineRollingModeOption {
 }
 
 export interface TimelineTooltipOption {
-  followMouse: boolean;
-  overflowMethod: 'cap' | 'flip';
+  followMouse?: boolean;
+  overflowMethod?: 'cap' | 'flip';
 }
 
 export type TimelineOptionsConfigureFunction = (option: string, path: string[]) => boolean;