The Grammy nominated singer has recently made the transition into the film world with two high profile roles in movies Hidden Figures and Moonlight. However, Barry revealed the singer, who played the role of Teresa in his movie, was quivering at the thought of making her first real movie appearance in his hit film.

Speaking at the Ritzy Picturehouse in Brixton, London on Monday evening (13Feb17), Barry praised the humble singer who arrived on set without an entourage.

"She wasn't world famous for us, she showed up by herself, her hair is everywhere," he told the audience. "Talking about her I have to talk about Mahershala (Ali) a bit. One of my favourite filmmakers is Lynne Ramsay, and she always blended actors with non-actors and Mahershala essentially, except for that one scene with Naomie (Harris), is working with all non first-time actors and so I would watch him with Janelle and her scenes with him."

"There's a couple scenes with Janelle and Mahershala, I think are great performances and you would see Mahershala helping Janelle to find her way," he explained. "She was very nervous because she's very accomplished in one medium and she started from scratch in another medium. And I told her there are no mistakes."

Janelle's performances in both Moonlight and Hidden Figures have garnered the Tightrope singer a Critics’ Choice Movie Award nomination and praise from the critics. She has previously spoken of feeling insecure about her acting ability and sought reassurance from Hidden Figures co-producer Pharrell Williams.

"He (Pharrell) pulled me to the side and he said, 'Listen, I just want you to know that I believe in you as an actor, I believe in your ability to do movies. You must continue to pursue this,'" she recalled to the New York Times. "I said, 'O.K., Pharrell. All right. If you say so.'"