Clean Thesis template, change title font

I am using the wonderful Clean Thesis template, which works really nice but now I am stuggeling of changing the font of thesisTitle and thesisSubtitle to Helvitica. So far i insert fontseries{n}fontfamily{phv}selectfont but where do I have to do it here?

documentclass{scrreprt}
usepackage[utf8]{inputenc}    
usepackage[english]{babel}     

newcommand{thesisTitle}{Effect of sugar on my hair, hand and ears}
newcommand{thesisSubtitle}{What happens if I eat to much of it?}
newcommand{thesisName}{Sugarcan and Coffeepot}
newcommand{thesisSubject}{Promising thing}
newcommand{thesisDate}{Today 2020}
newcommand{thesisVersion}{Second Version}

% Cover page content
subject{vspace{4.5cm} thesisSubject}

title{thesisTitle}
subtitle{thesisSubtitle}
author{thesisName}
date{thesisDate}


begin{document}
maketitle                                  % making the title
end{document}