The 23-year-old singer-turned-actress will play Christian Grey's adopted sister Mia in the movie, opposite Jamie Dornan and Dakota Johnson, reported MTV online.
"The film adaptation will surprise viewers. I am so excited for it," Ora said.
Ora also spoke about working with the director Sam Taylor-Wood.
"Oh, I was nervous because it was the first time I ever did a movie with words. But it was so nice. The director Sam, she was incredible, so it was all love."
'Fifty Shades of Grey' is set for a February 13, 2015 release in the US and UK.