Rihanna, who is pregnant with her and A$AP Rocky’s third baby, stepped out at the Smurfs Los Angeles premiere with her sons 3-year-old RZA and 23-month-old Riot.

Costume designer Alexandra Byrne has dressed interstellar beings (2011’s Thor), Earth’s mightiest heroes (2012’s The Avengers), a space-faring found family (2014’s Guardians of the Galaxy), and ...