"I'm speaking to you from my heart. Look, I don't know if I'm going to have a career after this, but f*** that.
The actor went on to say: "I need you to understand how painful this s**t is. I need you to understand how painful it is to be reminded every day that your race means nothing and that isn't the case anymore, that was never the case anymore."
Thousands gathered at Hyde Park on June 3 to protest against racism and police brutality.
Later on, the Star Wars Twitter account made a statement in support of "their hero" Boyega.
"Lucasfilm stands with John Boyega, and his message that, 'Now is the time. Black lives have always mattered. Black lives have always been important. Black lives have always meant something.' The evil that is racism must stop. We will commit to being part of the changes that is long overdue in the world."
Boyega's Star Wars co-star Mark Hamill also showed his support, tweeting that he had never been prouder of him and signing off, "love, dad".
The Last Jedi director Rian Johnson wrote "Love this man" of Boyega on Twitter.