diff --git a/toxcore/Messenger.c b/toxcore/Messenger.c
index be3d82e0..c73161d3 100644
--- a/toxcore/Messenger.c
+++ b/toxcore/Messenger.c
@@ -868,13 +868,36 @@ int m_group_peername(Messenger *m, int groupnumber, int peernumber, uint8_t *nam
 
     return group_peername(m->chats[groupnumber], peernumber, name);
 }
+
+/* Store the fact that we invited a specific friend.
+ */
+static void group_store_friendinvite(Messenger *m, int friendnumber, int groupnumber)
+{
+    /* Add 1 to the groupchat number because 0 (default value in invited_groups) is a valid groupchat number */
+    m->friendlist[friendnumber].invited_groups[m->friendlist[friendnumber].invited_groups_num % MAX_INVITED_GROUPS] =
+        groupnumber + 1;
+    ++m->friendlist[friendnumber].invited_groups_num;
+}
+
 /* return 1 if that friend was invited to the group
  * return 0 if the friend was not or error.
  */
 static uint8_t group_invited(Messenger *m, int friendnumber, int groupnumber)
 {
-    //TODO: this function;
-    return 1;
+
+    uint32_t i;
+    uint16_t num = MAX_INVITED_GROUPS;
+
+    if (MAX_INVITED_GROUPS > m->friendlist[friendnumber].invited_groups_num)
+        num = m->friendlist[friendnumber].invited_groups_num;
+
+    for (i = 0; i < num; ++i) {
+        if (m->friendlist[friendnumber].invited_groups[i] == groupnumber + 1) {
+            return 1;
+        }
+    }
+
+    return 0;
 }
 
 /* invite friendnumber to groupnumber
@@ -892,7 +915,8 @@ int invite_friend(Messenger *m, int friendnumber, int groupnumber)
     if (m->friendlist[friendnumber].status == NOFRIEND || m->chats[groupnumber] == NULL)
         return -1;
 
-    //TODO: store invited friends.
+    group_store_friendinvite(m, friendnumber, groupnumber);
+
     if (write_cryptpacket_id(m, friendnumber, PACKET_ID_INVITE_GROUPCHAT, m->chats[groupnumber]->self_public_key,
                              crypto_box_PUBLICKEYBYTES) == 0)
         return -1;
diff --git a/toxcore/Messenger.h b/toxcore/Messenger.h
index aa9d8632..10ac0eae 100644
--- a/toxcore/Messenger.h
+++ b/toxcore/Messenger.h
@@ -52,6 +52,9 @@
 #define PACKET_ID_JOIN_GROUPCHAT 145
 #define PACKET_ID_ACCEPT_GROUPCHAT 146
 
+/* Max number of groups we can invite someone at the same time to. */
+#define MAX_INVITED_GROUPS 64
+
 /* Status definitions. */
 enum {
     NOFRIEND,
@@ -148,6 +151,8 @@ typedef struct {
     uint64_t ping_lastsent;
     struct File_Transfers file_sending[MAX_CONCURRENT_FILE_PIPES];
     struct File_Transfers file_receiving[MAX_CONCURRENT_FILE_PIPES];
+    int invited_groups[MAX_INVITED_GROUPS];
+    uint16_t invited_groups_num;
 } Friend;
 
 typedef struct Messenger {