"Look, I'm not going to trivialise that situation, I just heard about it for the first time," McConaughey said.
"But I always told [director] Jeff Nichols this, look in Mud, the whole trailer for Mud could be Sam Shepard sitting in that green chair telling the boy about who Mud is. It would be about a two-and-a-half minute trailer, but it would have been really badass."
Still in disbelief, the actor ended the interview by saying, "He moved on today?"
"We lost one of the great ones. Great writer, great mind. All right, see you in the next one, Sam."
It was revealed yesterday that Shepard, the Pulitzer Prize-winning playwright and Oscar-nominated actor died last Thursday at his home in Kentucky from complications related to Lou Gehrig's disease.