Dr. Edmund Johnston appears in the Farscape episode "A Constellation Of Doubt." A professor of cognitive behaviorism at Stanford University, Johnston is one of several experts who appear as "talking heads" in Alien Visitation.
At one point, Johnston weighs in on Chiana's behavior as she experiments with make-up. Johnston speaks approvingly, saying that in light of "her otherworldly origins, Chiana's perspective is consistent, well-thought-out and, in my view, correct."
Executive producer Brian Henson was convinced to play the part when he was visiting the set on one of the last days of filming, according to a special feature on the DVD release.