Rachel made her acceptance speech in sign language after promising her six-year-old co-star Maisie Sly - who plays deaf child Libby in the film - that she would do so, and she can't wait to go home to show her family and friends the award.
Collecting the award, the film's writer and producer Rachel Shenton - a former Hollyoaks actress - delivered a speech in sign language, in which she called for better access to education for deaf children.
Shenton was also awarded Best Actress for her work on the film at the London Independent Film Festival a year ago.
Rachel Shenton has come a long way since playing Mitzeee Minniver in Hollyoaks. Rachel, 30, took to the stage with her fiancé Chris Overton - who played cage fighter Liam McAllister in the Channel 4 soap - to accept the trophy for her film The Silent Child, which tells the story of a deaf little girl.
The screen star, from Caverswall, near Stoke, said: "I made a promise to our six-year-old lead actress that I'd sign this speech".
Admitting the win still hadn't sunk in, she added: "We were being serious when we were saying we're so honoured to be nominated, we really, really meant it".
Celebrities have worn black at various events such as the BAFTAs and the Golden Globes to show their support for the movement, however Emma Watson chose to take it that step further when she turned up to the red carpet at the Oscars with a new tattoo.
"It's not exaggerated or sensationalised for the movie".
Chatting to hosts Holly Willoughby and Phillip Schofield live from LA, Rachel and Chris revealed they celebrated their unexpected win with a burger, most of which ended up over their Oscar. You can't see it and it's not life-threatening, so I want to say the biggest of thank you's to the Academy for allowing us to put this in front of a mainstream audience. And my kids. And I wanna say, like Jimmy Cagney said once, 'My mother thanks you, my father thanks you, my brothers and sisters thank you. So, deafness is a silent disability.