The actor and Colbert performed a sketch called "Big Questions with Even Bigger Stars," while pretending to be on a picnic, lying on a blanket. The skit marked a rare TV appearance for Pitt since he and Angelina Jolie announced they were divorcing last year.
"I haven't been out in a while. It feels good, feels good," Pitt said.
The two got deep as they lobbed questions back and forth about the meaning of life, setting each other up for jokes.