diff --git a/packages/mermaid/src/diagrams/class/classDb.ts b/packages/mermaid/src/diagrams/class/classDb.ts
index 312dda7a6..d61573ded 100644
--- a/packages/mermaid/src/diagrams/class/classDb.ts
+++ b/packages/mermaid/src/diagrams/class/classDb.ts
@@ -446,11 +446,13 @@ const getNamespaces = function (): NamespaceMap {
  * @public
  */
 export const addClassesToNamespace = function (id: string, classNames: string[]) {
-  if (namespaces[id] !== undefined) {
-    classNames.map((className) => {
-      classes[className].parent = id;
-      namespaces[id].classes[className] = classes[className];
-    });
+  if (namespaces[id] === undefined) {
+    return;
+  }
+  for (const name of classNames) {
+    const { className } = splitClassNameAndType(name);
+    classes[className].parent = id;
+    namespaces[id].classes[className] = classes[className];
   }
 };
 
diff --git a/packages/mermaid/src/diagrams/class/classDiagram.spec.ts b/packages/mermaid/src/diagrams/class/classDiagram.spec.ts
index 532c8aaa7..fb719658e 100644
--- a/packages/mermaid/src/diagrams/class/classDiagram.spec.ts
+++ b/packages/mermaid/src/diagrams/class/classDiagram.spec.ts
@@ -1043,6 +1043,19 @@ foo()
 `;
       parser.parse(str);
     });
+
+    it('should handle namespace with generic types', () => {
+      parser.parse(`classDiagram
+
+namespace space {
+    class Square~Shape~{
+        int id
+        List~int~ position
+        setPoints(List~int~ points)
+        getPoints() List~int~
+    }
+}`);
+    });
   });
 });