Teen dreams Taylor Swift and Zac Efron stopped by The Ellen DeGeneres Show today to chat with Ellen about the host's favorite topic: their dating lives. Swift revealed that she'd given her friend Efron his first lesson on the guitar, and they dueted together on Foster the People's "Pumped Up Kicks," eventually changing the lyrics to reflect their fondness for Ellen's invasive questioning. The results are pretty adorable – and Efron holds his own on the six-string, too.