Robert Duvall, as actor People & Technology

Robert Duvall (born January 5, 1931) is an American actor known for The Godfather, Apocalypse Now, and Tender Mercies. He appears uncredited in Invasion of the Body Snatchers (1978) as a silent priest on a playground swing — already a pod.

In the wiki

• Kevin McCarthy and Don Siegel Cameos describes Duvall's uncredited cameo and Kaufman's explanation: "if you're going to make a horror movie, you've got to have a priest in it."
• Cast and Characters (Invasion of the Body Snatchers) notes the cameo in the cast listing.