Denzel Washington is convinced Viola Davis will win an Oscar for 'Fences'.

Denzel Washington

Denzel Washington

The 62-year-old actor was overwhelmed by his co-star's performance in the 1950s family drama and thinks there are few people who will ever match the work she has done in the movie, for which she is up for Best Supporting Actress.

He gushed: "She kills it. I was like, 'Why do I even have to be in this movie?' She kills it.

"Viola gives one of the greatest performances of all time in this. Period.

"I've been around a long time ago and you never know what's going to happen with Oscars and awards, but... she's gonna win it this year. She has to."

But Viola credits her co-star's support and the film's director as helping her bring out her best performance because he was so reassuring and understanding.

She told Total Film magazine: "Oh my God, I had no sleep for days worrying about one big scene.

"My big monologue with Cory is four or five pages long. I kept reading it over and over again but I never really got it.

"One day Denzel watched me do the scene and he said, 'Let's do it again, but this time I want you to slap him. Hard.' I said, 'Really?' He said, 'Sure, slap the p**s out of him. Hit him as many times as you want. Take all that pain and emotion and slap him.' So I did. And it worked.

"It opened the whole scene up and made me get it.

"Denzel told me, 'It's not a monologue. It's not about you. It's about him. He's the one listening to you. Help him.' We were all so lucky to have a director who actually understands that."

'Fences' is also up for Best Picture, Best Actor for Denzel and Best Writing Adapted Screenplay.