Comedy Central
Colbert played coy and focused the opening segment of his show in praise of Letterman, who he said had been one of his idols when he was younger.
"I learned more from watching Dave than I did from going to my classes," Colbert said, noting Letterman had started on late night during Colbert's freshman year in college. "Especially the ones I did not go to because I had stayed up until 1:30 watching Dave."
Colbert said Letterman has influenced every host who came after him - and "even a few who came before him, he's that good."
"I have to tell you - I do not envy whoever they try to put in that chair," Colbert said, earning a raucous round of applause from the studio audience. "Those are some huge shoes to fill."