Failed presidential candidate Hillary Clinton praised 16-year-old climate activist Greta Thunberg as a “gutsy woman” on Facebook Thursday.

“One of my favorite #gutsywomen: Greta Thunberg, the Swedish activist whose school strikes for climate action have inspired a global climate strike that will start tomorrow,” Clinton wrote on Thursday on Facebook.

American schools are preparing for the student climate school strikes organized Friday for students to highlight climate change.

New York City’s Department of Education has already promised to excuse absences of students participating in the climate strike if they have parental consent.

Thunberg traveled to the United States to lead the school strike, which will take place in 150 different countries ahead of the United Nations climate summit in New York City next week. Thunberg also took a year off of school to protest the global threat posed by climate change.

“If you can’t be in the strike, then, of course, you don’t have to,” she said in an interview with Teen Vogue. “But I think if there is one day you should join, this is the day.”

Since losing the presidential election to President Donald Trump, Clinton has championed the cause of women activists. She is currently touring the United States to promote her new book, The Book of Gutsy Women, co-authored with her daughter, Chelsea Clinton.