Susan Sarandon will not let "a little slip" stop her from promoting her cause.

The 73-year-old American actress shocked her fans on Friday (Nov 22) when she posted on Instagram photos of her with a black eye and a swelling on her forehead.

Sarandon, who won a Best Actress Oscar in 1996 for Dead Man Walking, did not disclose when the fall occurred, but said she suffered a "concussion, fractured nose, banged up knee".

The star of films such as Thelma & Louise (1991) and The Client (1994) was due to speak on Saturday at a town hall held by American senator Bernie Sanders, who is bidding to be the United States presidential candidate for the Democratic Party.

Sarandon had to cancel her appearance due to her injuries, but she used her post to share part of her planned speech, where she talked about issues like climate change, the opioid crisis and gun violence in the US.

She was a vocal supporter of Mr Sanders during the 2016 US presidential campaign and angered some Democrats when she said then that she would not vote for Mrs Hillary Clinton, who won the party's nomination.

Sarandon's injury came a week after her daughter, actress Eva Amurri, announced that she was separating from her husband Kyle Martino. The couple have a five-year-old daughter and a three-year-old son, and Amurri is pregnant with their third child.