diff --git a/common/js/types.d.ts b/common/js/types.d.ts
index 1ef4df605..c20aa590d 100644
--- a/common/js/types.d.ts
+++ b/common/js/types.d.ts
@@ -526,6 +526,7 @@ interface ChartDocumentData {
 }
 export interface ChartDocument<G extends Game = Game, P extends Playtypes[G] = Playtypes[G], I extends IDStrings = IDStrings> extends MongoDBDocument {
     chartID: string;
+    rgcID: string | null;
     songID: integer;
     level: string;
     levelNum: number;
diff --git a/common/src/types.ts b/common/src/types.ts
index 6c3855a37..2840becef 100644
--- a/common/src/types.ts
+++ b/common/src/types.ts
@@ -709,6 +709,7 @@ export interface ChartDocument<
     I extends IDStrings = IDStrings
 > extends MongoDBDocument {
     chartID: string;
+    rgcID: string | null; // ID to perform backbeat lookup in future.
     songID: integer;
     level: string;
     levelNum: number;