Back in the 1950s and 1960s, when television was in its infancy, it was common for actors to appear in advertisements during the show in which they starred. Often this occurred with the actor pitching a product while outfitted in wardrobe and makeup in the same way they appeared on a show. The practice of having actors promote a brand was a carryover from the golden days of radio, where program sponsors (i.e., advertisers) demanded actors participate in ads in order to fund a program.
By the 1970s, the practice of actors supporting sponsors faded, as advertisers moved away from funding of a specific television show and, instead, opted to purchase shorter spots, such as 60 second ads, across multiple TV programs.
Now, according to this New York Times story, cast member promotion of products is returning. The story reports on cast member promotions for ABC and NBC owned programs. As was the strategy in the 1950s and 1960s, it seems the ads will appear within the actor’s show. Brands using this strategy include Target, Dodge and Jeep.