Samsung Electronics Co. spent an estimated $20 million on ads to run during breaks in the Academy Awards broadcast on Sunday night. But Samsung may have got more promotional mileage from Oscars host Ellen DeGeneres during the show itself.

While the stunt felt spontaneous, it wasn't entirely unplanned. As part of its sponsorship and ad pact for the Oscars with ABC, the TV network airing the show, Samsung and its media buying firm Starcom MediaVest negotiated to have its Galaxy smartphone integrated into the show, according to two people familiar with the matter.

Ms. DeGeneres, in the days leading up to the broadcast, decided she wanted to take "selfies" during the show and ABC suggested she use a Samsung since it was a sponsor, another person familiar with the matter said. During rehearsals Samsung executives trained Ms. DeGeneres on how to use the Samsung Galaxy, two people familiar with the matter said.