Here's a clip of Neil Armstrong, semi-reclusive Gemini 8 and Apollo 11 astronaut, doing a TV spot for Chrysler vehicles in 1979. Neil did a pretty good job at being a pitchman despite not having acting experience; being a living symbol of one of the greatest engineering feats of all time certainly added to his credibility as an automobile company's spokesman.
Many have wondered why Neil chose to advertise vehicles in the late 1970s. Well, when you were the first man to step on the Moon's surface, I'm pretty sure you can do whatever the hell you want. There's your answer.