A few shots were Tweeted from the set by Martin and "Glee" star Lea Michele:
Martin, who was also seen on Broadway in the original run of Les Miserables, will play a Spanish teacher; he will reportedly take part in two musical numbers in the upcoming episode.
"Glee" airs Tuesday nights on Fox at 8 PM ET.
The Broadway revival of Evita begins previews March 12 at the Marquis Theatre.