diff --git a/front/app/_orgs/[orgslug]/course/[courseid]/lecture/[lectureid]/page.tsx b/front/app/_orgs/[orgslug]/course/[courseid]/lecture/[lectureid]/page.tsx
index 8deb297b..2ddcc840 100644
--- a/front/app/_orgs/[orgslug]/course/[courseid]/lecture/[lectureid]/page.tsx
+++ b/front/app/_orgs/[orgslug]/course/[courseid]/lecture/[lectureid]/page.tsx
@@ -10,6 +10,7 @@ import styled from "styled-components";
 import { getCourse, getCourseMetadata } from "../../../../../../../services/courses/courses";
 import VideoLecture from "@components/LectureViews/Video/Video";
 import { Check } from "lucide-react";
+import { maskLectureAsComplete } from "@services/courses/activity";
 
 function LecturePage(params: any) {
   const router = useRouter();
@@ -32,6 +33,11 @@ function LecturePage(params: any) {
     setIsLoading(false);
   }
 
+  async function markLectureAsCompleteFront() {
+    const activity = await maskLectureAsComplete("" + lectureid, courseid, lecture.lecture_id.replace("lecture_", ""));
+    fetchCourseData();
+  }
+
   React.useEffect(() => {
     if (lectureid) {
       fetchLectureData();
@@ -85,10 +91,24 @@ function LecturePage(params: any) {
             {lecture.type == "video" && <VideoLecture course={course} lecture={lecture} />}
 
             <ActivityMarkerWrapper>
-              <button> <i><Check size={20}></Check></i> Mark as complete</button>
+              {course.activity.lectures_marked_complete.includes("lecture_"+lectureid) ? (
+                <button style={{ backgroundColor: "green" }}>
+                  <i>
+                    <Check size={20}></Check>
+                  </i>{" "}
+                  Already completed
+                </button>
+              ) : (
+                <button onClick={markLectureAsCompleteFront}>
+                  {" "}
+                  <i>
+                    <Check size={20}></Check>
+                  </i>{" "}
+                  Mark as complete
+                </button>
+              )}
             </ActivityMarkerWrapper>
           </CourseContent>
-          
         </LectureLayout>
       )}
     </>
@@ -169,8 +189,7 @@ const ActivityMarkerWrapper = styled.div`
   margin: 0 auto;
   align-items: center;
 
-
-  button{
+  button {
     background-color: #151515;
     border: none;
     padding: 18px;
@@ -190,20 +209,17 @@ const ActivityMarkerWrapper = styled.div`
     font-size: 16px;
     letter-spacing: -0.05em;
     box-shadow: 0px 13px 33px -13px rgba(0, 0, 0, 0.42);
-    
 
-    i{
+    i {
       margin-right: 5px;
 
       // center the icon
       display: flex;
       align-items: center;
       justify-content: center;
-
-  
     }
 
-    &:hover{
+    &:hover {
       background-color: #000000;
     }
   }
diff --git a/front/services/courses/activity.ts b/front/services/courses/activity.ts
index d1da007f..0185e5d1 100644
--- a/front/services/courses/activity.ts
+++ b/front/services/courses/activity.ts
@@ -22,3 +22,10 @@ export async function closeActivity(org_id: string, activity_id: string) {
     .catch((error) => console.log("error", error));
   return result;
 }
+
+export async function maskLectureAsComplete(org_id: string, course_id: string, lecture_id: string) {
+  const result: any = await fetch(`${getAPIUrl()}activity/${org_id}/add_lecture/${course_id}/${lecture_id}`, RequestBody("POST", null))
+    .then((result) => result.json())
+    .catch((error) => console.log("error", error));
+  return result;
+}
diff --git a/src/services/activity.py b/src/services/activity.py
index 6b621740..9d8048cf 100644
--- a/src/services/activity.py
+++ b/src/services/activity.py
@@ -1,3 +1,4 @@
+from cmath import log
 from datetime import datetime
 import json
 from typing import List, Literal, Optional
@@ -14,8 +15,8 @@ class Activity(BaseModel):
     course_id: str
     status:  Optional[Literal['ongoing', 'done', 'closed']] = 'ongoing'
     masked: Optional[bool] = False
-    lectures_marked_complete: Optional[List[str]]
-    lectures_data: Optional[List[dict]]
+    lectures_marked_complete: Optional[List[str]] = []
+    lectures_data: Optional[List[dict]] = []
 
 
 class ActivityInDB(Activity):
@@ -70,29 +71,28 @@ async def get_user_activities(request: Request, user: PublicUser, org_id: str):
 
 async def add_lecture_to_activity(request: Request, user: PublicUser, org_id: str, course_id: str, lecture_id: str):
     activities = request.app.db["activities"]
-
+    print(lecture_id)
+    course_id = f"course_{course_id}"
+    lecture_id = f"lecture_{lecture_id}"
+    print(lecture_id)
     activity = activities.find_one(
         {"course_id": course_id,
-            "user_id": user.user_id,
-            "org_id": org_id
-         })
+            "user_id": user.user_id
+         },  {'_id': 0})
 
     if not activity:
         raise HTTPException(
             status_code=status.HTTP_409_CONFLICT, detail="Activity not found")
 
-    if lecture_id in activity['lectures_marked_complete']:
+    if lecture_id not in activity['lectures_marked_complete']:
+        activity['lectures_marked_complete'].append(str(lecture_id))
+        activities.update_one(
+            {"activity_id": activity['activity_id']}, {"$set": activity})
+        return activity
+    else:
         raise HTTPException(
             status_code=status.HTTP_409_CONFLICT, detail="Lecture already marked complete")
 
-    activity['lectures_marked_complete'].append(lecture_id)
-
-    activities.update_one(
-        {"activity_id": activity['activity_id']}, {"$set": activity})
-
-    # send 200 custom message
-    return {"message": "Lecture added to activity"}
-
 
 async def close_activity(request: Request, user: PublicUser,  activity_id: str, org_id: str,):
     activities = request.app.db["activities"]