Black Lives Matter: Serena Williams speaks up on the fear of driving while black

Tennis star Serena Williams has added her voice to concern about police injustice and brutality in the United States.

Williams narrated a recent encounter with the police, on her Facebook page; when she became frightened and regretted asking her nephew to drive.

In the post, the world number two, said sight of the police reminded her of the 'horrible video of the woman in the car when a cop shot her boyfriend.'

That is most likely a reference to the case of the Philando Castile who was killed in his car by police in Minnesota. His girlfriend live streamed the aftermath of the shooting. Related: Black Lives Matter: 'There is a sense of vulnerability' - Ghanaians in Minnesota

'I won't be silenced'; she wrote and quoted a famous saying by civil rights leader Martin Luther King; 'There comes a time when silence is betrayal.'

Serena Williams is the latest personality to join calls for improved policing following the likes of Beyonce, Alicia Keys and Colin Kaepernick (who refuses to stand when the US national anthem is played).

Black people in the US have been protesting in the last two years; since the shooting of Michael Brown, about being disproportionately policed and targeted by a largely white police force. Related: Black Lives Matter: Gun and justice reforms needed - Obama

Last week, violent protest broke out in Charlotte, North Carolina following the shooting of a black man who the police say was holding a gun; a claim that has been widely disputed by many others.  

Below is the post by the tennis champion Serena Williams.

Today I asked my 18 year old nephew (to be clear he's black) to drive me to my meetings so I can work on my phone #safteyfirst . In the distance I saw cop on the side of the road. I quickly checked to see if he was obliging by the speed limit. Than I remembered that horrible video of the woman in the car when a cop shot her boyfriend.

All of this went through my mind in a matter of seconds. I even regretted not driving myself. I would never forgive myself if something happened to my nephew. He's so innocent. So were all "the others" Related: MTV VMAs 2016: Beyonce appears at award ceremony with mothers of 4 black men killed by police

I am a total believer that not "everyone" is bad It is just the ones that are ignorant, afraid, uneducated, and insensitive that is affecting millions and millions of lives.

Why did I have to think about this in 2016? Have we not gone through enough, opened so many doors, impacted billions of lives? But I realized we must stride on- for it's not how far we have come but how much further still we have to go.

I than wondered than have I spoken up? I had to take a look at me. What about my nephews? What if I have a son and what about my daughters?

As Dr. Martin Luther King said "There comes a time when silence is betrayal".

I Won't Be Silent
Serena