function bp_groups_membership_accepted_add_activity( $user_id, $group_id ) {

	// Bail if Activity is not active.
	if ( ! bp_is_active( 'activity' ) ) {
		return false;
	}

	// Get the group so we can get it's name.
	$group = groups_get_group( $group_id );

	/**
	 * Filters the 'membership_accepted' activity actions.
	 *
	 * @since 1.2.0
	 *
	 * @param string $value    The 'membership_accepted' activity action.
	 * @param int    $user_id  ID of the user joining the group.
	 * @param int    $group_id ID of the group. Passed by reference.
	 */
	$action = apply_filters_ref_array( 'groups_activity_membership_accepted_action', array( sprintf( __( '%1$s joined the group %2$s', 'buddypress' ), bp_core_get_userlink( $user_id ), '<a href="' . bp_get_group_permalink( $group ) . '">' . esc_attr( $group->name ) . '</a>' ), $user_id, &$group ) );

	// Record in activity streams.
	groups_record_activity( array(
		'action'  => $action,
		'type'    => 'joined_group',
		'item_id' => $group_id,
		'user_id' => $user_id
	) );
}