"The NHS is in its most perilous position in its history," she pointed out.
The union reached a tentative agreement with studios and producers on Wednesday, after nearly four months on strike.
Former President Donald Trump, the leading Republican seeking to unseat Biden, is also courting autoworkers with a rally in Detroit.
"Patients are at risk every single day of the week," she claimed.
"How can you get to a point where this is going to end if you’re not actually talking to them?”
Johnson’s donation to SAG-AFTRA will reportedly help 7,000 to 10,000 of his fellow union members.
Here are some ways writers and actors want the public to support them during the strikes.
Star Kimiko Glenn talked about cast members' low wages in a TikTok addressing the current SAG-AFTRA actors strike.
One in 10 of us are now following the internet's inaccurate health advice.