The film Firecreek starring Stewart and Henry Fonda was released in January of 1968. Warner Brothers-Seven Arts issued a special 12-inch, 33 1/3 RPM record (WBSA-4890) with five spots to help promote the film on radio.
Stewart’s voice is not heard on any of the five tracks.
Here are the two 60-second spots:
There also were two 30-second spots:
Finally, there was a 10-second spot: