The 32-year-old singer was impressed by Lupita's stunning light blue silk georgette gown at the 86th Academy Awards, reported Contactmusic.
"Lupita's just gorgeous. She has an inner glow about her as well, she shines bright from the inside. She's not afraid to wear fun, bright colours, like that really beautiful blue she wore at the Oscars," Roberts said.
The singer also admires supermodel Kate Moss.
"Kate Moss, obviously, she's fabulous. Rita Ora can go real out there with her fashion, but then there's some stuff that she does that just love, I think it's so cool and funky. And Rosie Huntington-Whiteley, I'm a little obsessed with her," she said.