diff --git a/web/modals/threads/members/add-members-modal.react.js b/web/modals/threads/members/add-members-modal.react.js
index 3d0e90814..3998aafcd 100644
--- a/web/modals/threads/members/add-members-modal.react.js
+++ b/web/modals/threads/members/add-members-modal.react.js
@@ -1,123 +1,137 @@
 // @flow
 
 import * as React from 'react';
 
 import {
   changeThreadSettingsActionTypes,
   useChangeThreadSettings,
 } from 'lib/actions/thread-actions.js';
+import { threadInfoSelector } from 'lib/selectors/thread-selectors.js';
+import { useAddDMThreadMembers } from 'lib/shared/dm-ops/dm-op-utils.js';
+import { threadTypeIsThick } from 'lib/types/thread-types-enum.js';
 import { useDispatchActionPromise } from 'lib/utils/redux-promise-utils.js';
+import { useSelector } from 'lib/utils/redux-utils.js';
 
 import css from './members-modal.css';
 import Button from '../../../components/button.react.js';
 import {
   AddUsersListProvider,
   useAddUsersListContext,
 } from '../../../settings/relationship/add-users-list-provider.react.js';
 import AddUsersList from '../../../settings/relationship/add-users-list.react.js';
 import { useAddMembersListUserInfos } from '../../../settings/relationship/add-users-utils.js';
 import SearchModal from '../../search-modal.react.js';
 
 type ContentProps = {
   +searchText: string,
   +threadID: string,
 };
 
 function AddMembersList(props: ContentProps): React.Node {
   const { searchText, threadID } = props;
 
   const { userInfos, sortedUsersWithENSNames } = useAddMembersListUserInfos({
     threadID,
     searchText,
   });
 
   const addMembersList = React.useMemo(
     () => (
       <div className={css.addMembersListContainer}>
         <AddUsersList
           searchModeActive={searchText.length > 0}
           userInfos={userInfos}
           sortedUsersWithENSNames={sortedUsersWithENSNames}
         />
       </div>
     ),
     [searchText.length, sortedUsersWithENSNames, userInfos],
   );
 
   return addMembersList;
 }
 
 type Props = {
   +threadID: string,
   +onClose: () => void,
 };
 
 function AddMembersModalContent(props: Props): React.Node {
   const { threadID, onClose } = props;
 
   const { pendingUsersToAdd } = useAddUsersListContext();
 
   const dispatchActionPromise = useDispatchActionPromise();
   const callChangeThreadSettings = useChangeThreadSettings();
+  const addDMThreadMembers = useAddDMThreadMembers();
+  const threadInfo = useSelector(state => threadInfoSelector(state)[threadID]);
 
   const addUsers = React.useCallback(() => {
-    void dispatchActionPromise(
-      changeThreadSettingsActionTypes,
-      callChangeThreadSettings({
-        threadID,
-        changes: { newMemberIDs: Array.from(pendingUsersToAdd.keys()) },
-      }),
-    );
+    const newMemberIDs = Array.from(pendingUsersToAdd.keys());
+
+    if (threadTypeIsThick(threadInfo.type)) {
+      void addDMThreadMembers(newMemberIDs, threadInfo);
+    } else {
+      void dispatchActionPromise(
+        changeThreadSettingsActionTypes,
+        callChangeThreadSettings({
+          threadID,
+          changes: { newMemberIDs },
+        }),
+      );
+    }
     onClose();
   }, [
+    addDMThreadMembers,
     callChangeThreadSettings,
     dispatchActionPromise,
     onClose,
     pendingUsersToAdd,
     threadID,
+    threadInfo,
   ]);
 
   const primaryButton = React.useMemo(
     () => (
       <Button
         disabled={!pendingUsersToAdd.size}
         variant="filled"
         onClick={addUsers}
       >
         Add selected members
       </Button>
     ),
     [addUsers, pendingUsersToAdd.size],
   );
 
   const addMembersList = React.useCallback(
     (searchText: string) => (
       <AddMembersList searchText={searchText} threadID={threadID} />
     ),
     [threadID],
   );
 
   return (
     <SearchModal
       name="Add members"
       searchPlaceholder="Search members"
       onClose={onClose}
       size="large"
       primaryButton={primaryButton}
     >
       {addMembersList}
     </SearchModal>
   );
 }
 
 function AddMembersModal(props: Props): React.Node {
   const { threadID, onClose } = props;
 
   return (
     <AddUsersListProvider>
       <AddMembersModalContent threadID={threadID} onClose={onClose} />
     </AddUsersListProvider>
   );
 }
 
 export { AddMembersModal, AddMembersList };