The 'Umbrella' singer swapped her often risqué style for something more elegant, wearing a white scallop edge skirt and matching jacket to the press conference.
Rihanna, 25, was joined by her co-star, Big Bang Theory's Jim Parsons, at Saturday's junket.
Home is a computer animated comedy from Dreamworks about a relatively happy group of aliens who invade earth to protect themselves. Rihanna's teen character ends up befriending an outcast alien, voiced by Jim.
Other stars who lend their vocals to the movie include Steve Martin and Jennifer Lopez.
As well as providing her voice for the movie, Rihanna has also recorded a concept album scheduled for release next week. Songs she recorded for the movie include 'Towards The Sun' and 'Dancing In The Dark'.
She told MTV News: "I think music is important to every film. I think it sets the tone, in the moment. It creates the sensitivity, the suspense, no matter what film it is, especially in animation.
"I've had an incredible time making music for this film. I've worked really closely with Tim Johnson, the director, just to make sure that lyrically, and musically the songs were matching exactly what he needed — what he needed the audience to feel in that moment."
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