The pair have done so twice in the past week, and Tweeted pics of the results.
Last Tuesday, the pop star and the Glee actress dressed up "full-time fancy," in Swift's words, and went out with friends to dinner to celebrate Shirley MacLaine's 78th birthday.
"Had a long day & don't know what to celebrate later...? Because you need a moment to be young? Find your moments," Agron wrote after posting the photos.