Charlie Puth duets with Simon & Garfunkel’s Art Garfunkel, Jimmy Fallon at Madison Square Concert

In his online role as “Professor Puth,” Charlie Puth is usually the teacher, but Friday night at New York’s Madison Square Garden, he was the pupil.

Charlie brought out Rock & Roll Hall of Famer Art Garfunkel — who with Paul Simon made up the legendary duo Simon & Garfunkel — as a special guest. “He learned how to make his records from me and Paul. Producing, singing,” Art said of Charlie. “You’re my student.”

“I am your student,” Charlie confirmed. “I’m serious. I’m not just saying that because all these wonderful people are here.  The reason why I’m here right now is because of the music you’ve written with Paul. It’s amazing.”

Art, 84, then talked about the shifting popularity of various Simon & Garfunkel songs. “They all have their lifespans, but ‘The Boxer’ stays well loved,” he noted, before he and Charlie began duetting on the song. “The Boxer,” with its signature “lie-la-lie” chorus, was released in 1969 and reached the top 10.

It’s worth noting that “Carla’s Song,” a track on Harry Styles’ latest album, was inspired by another famous Simon & Garfunkel song, “Bridge Over Troubled Water.”

In addition to Art, Charlie also brought out a few other guests during the show. He and Jimmy Fallon teamed up to sing “Africa” by Toto, and rapper Busta Rhymes showed up to perform his songs “Break Ya Neck” and “Put Your Hands Where My Eyes Could See,” and his verse on Chris Brown’s “Look at Me Now.”  Gospel legend Kirk Franklin also joined Charlie to sing “I Smile,” “Lean on Me” and “Stomp.”