updated 09/22/2008 AT 11:00 AM ET
•originally published 09/22/2008 AT 12:05 PM ET
Josh Groban condensed 60 years of television history into four minutes, performing a medley of beloved TV show themes – and even changing his voice with each tune – on the Emmy Awards Sunday night.
But how did the singer pull off the marathon performance?
“A lot of rehearsal and a lot of coffee,” Groban said backstage at the PEOPLE photobooth, as he received congratulations from passersby.
“I delved into my childhood and even before my childhood,” Groban, 27, said of the medley, which wove together iconic themes from Friends, The Jeffersons, Happy Days and many more.
As for the shows that came before his time, “Thank god for Nick at Nite,” the singer joked. “That’s where I learned a lot of them. As a kid, I loved watching The Brady Bunch and I Love Lucy and Gilligan’s Island.”
The hardest part for Groban? Whistling the theme for The Andy Griffith Show.
“It was hard to whistle on stage, and there was a guy telling me to whistle over the microphone,” he said. “But I pulled it off.”