The Screen Actors Guild (SAG) has announced it will go on strike, marking the start of the largest Hollywood shutdown in decades.
About 160,000 performers will stop work at midnight, and they will join the Writers Guild of America, which has been striking since May 2.
SAG members want a fairer split of profits from streaming giants and better working conditions.
The unions are also concerned about the use of artificial intelligence and how it could be used in the industry