American actress Lili Reinhart has come out as bisexual in an Instagram post.

Reinhart, who stars in TV drama Riverdale, was promoting an LGBTQ+ protest for Black Lives Matter on her story when she announced her sexuality.

She wrote: “Although I've never announced it publicly before, I am a proud bisexual woman. And I will be joining this protest today. Come join.”

The 23 year-old has been very vocal on social media about the protests following George Floyd’s death.

She wrote: “I want to say that I am ashamed of the racism that exists in this country. We are taught to look at our police officers as helpful and friendly when we learn about ‘leaders’ in elementary school. Our ‘leaders’ have failed us today.

“I can’t begin to imagine the horror of worrying that you won’t be protected by your ‘leaders’ because of the colour of your skin. 

"I know that white privilege exists and I could never fully understand what it’s like to be oppressed because of my race. I don’t have all the right words, but I stand by you. #BlackLivesMatter.”

She has most recently dated Riverdale co-star Cole Sprouse but recent reports suggest the couple have broken up after three years together.