function bp_legacy_theme_get_single_activity_content() {
	if ( ! bp_is_post_request() ) {
		return;
	}

	$activity_array = bp_activity_get_specific( array(
		'activity_ids'     => $_POST['activity_id'],
		'display_comments' => 'stream'
	) );

	$activity = ! empty( $activity_array['activities'][0] ) ? $activity_array['activities'][0] : false;

	if ( empty( $activity ) )
		exit; // @todo: error?

	/**
	 * Fires before the return of an activity's full, non-excerpted content via a POST request.
	 *
	 * @since 1.7.0
	 *
	 * @param string $activity Activity content. Passed by reference.
	 */
	do_action_ref_array( 'bp_legacy_theme_get_single_activity_content', array( &$activity ) );

	// Activity content retrieved through AJAX should run through normal filters, but not be truncated.
	remove_filter( 'bp_get_activity_content_body', 'bp_activity_truncate_entry', 5 );

	/** This filter is documented in bp-activity/bp-activity-template.php */
	$content = apply_filters_ref_array( 'bp_get_activity_content_body', array( $activity->content, &$activity ) );

	exit( $content );
}