The War Machine actor and the late-night host, both 53, lay down on a blanket and stared up at the stars as they asked philosophical questions about the universe, humanity and the afterlife, among other topics.
"Wow, look at that night sky. It's so beautiful," Colbert said at the beginning of the seven-minute skit. Pitt replied, "It sure is. ... I haven't been out in a while. It feels good, feels good."
The Oscar winner then asked, "If the universe includes all of existence, what existed before the universe?" The comedian responded, "Probably a teaser trailer for the universe with, like, one really good scene that isn't even in the universe when it's released."
Later in the segment, Colbert said he saw "an endless void. No answers. No meaning. No way to construct coherence from the swirling chaos," before quipping that the cloud resembled White House Press Secretary Sean Spicer.
While in New York City on Tuesday, Pitt also attended the premiere of his upcoming Netflix film, War Machine, which premieres on Friday, May 26. He appeared to be in great spirits and looked slender in a black suit and a white button-down shirt.
The Late Show with Stephen Colbert airs on CBS weeknights at 11:35 p.m. ET.
Want stories like these delivered straight to your inbox? Sign up now for the Us Weekly newsletter!