Spotted: John Legend

[UPDATED]We just spotted John Legend on the steps of the Architecture building, dressed in black, posing for a photo with a huge group of students. We hear he's on campus for AAS 348/ENG 348: Black Popular Music Culture.After the "Ordinary People" crooner signed autographs and took photos, he disappeared toward Frist, leaving behind him a trail of awestruck Princeton students. "John! John!" they yelled as he retreated, signing course packets all the way. We saw one sophomore shake his head slowly, a smile of disbelief on his face, as he walked to class.No, really.UPDATE: Some more details from his visit after the jump, courtesy of a student in the class.  Turns out he's been working with this weekend's USG Lawnparties band, The Roots:

We're going through the history chronologically, and this is our week on hip-hop and last week was R&B, so he fit in nicely. He went to UPenn and one of his good friends is a professor there, and that professor was friends with our professors (Imani Perry and Daphne Brooks) so that's how he set it up.He mostly talked about his new album called "Wake Up" that he's doing with the Roots, which is going to be all covers of songs from the late 60's/early 70's (all the songs that they are covering were chosen by Questlove of the Roots and are all songs that have been sampled heavily in hip-hop/rap) - so basically they're doing covers, and all the songs are like socially conscious, like anti-war, vision for a better world, what it's like the live in the ghetto in a city etc.)He didn't sing, although he played a bunch of the songs from the new album (which he did sing along to, but they were also recorded... does that make sense?), but they weren't finished yet - like one song he said they were waiting on a verse from Common, but Common hadn't recorded it yet etc.Then the 2nd half of class he answered questions.