Use document title and document date in lyx fancyheader

Put this in your Lyx preamble (document -> settings -> preamble): \def\title#1{\gdef\@title{#1}\gdef\THETITLE{#1}} \def\date#1{\gdef\@date{#1}\gdef\THEDATE{#1}} \def\author#1{\gdef\@author{#1}\gdef\THEAUTHOR{#1}} \usepackage{fancyhdr} \pagestyle{fancy} \newcommand{\helv}{% \fontfamily{phv}\fontseries{b}\fontsize{10}{10}\selectfont} \lhead{\helv \THETITLE - \THEDATE } \rhead{\helv \THEAUTHOR} \usepackage{lastpage} \cfoot{\thepage\ / \pageref{LastPage}}