Garner was already in town Tuesday with her parents to promote a cause that's close to her heart.
Garner was joined by her mom while reading the book, "Is Your Mamma a Llama," to kids at the Rosemount Center in Northwest. Her dad stood nearby and watched.
The Hollywood A-lister was in town to promote early childhood education, including programs like Head Start.
"As a mother of two girls, as an advocate for children, and as a citizen, I cannot accept an America that fails them and forgoes a brighter future for them," she said at a news conference before reading time.
Garner grew up in rural West Virginia. With Mother's Day coming up this weekend, she gave a special thanks to her mom's influence on her education.
Garner is an ambassador for the group called Save the Children. The organization just released a report showing that two-thirds of America's fourth-graders are reading below grade level.
Also, while rating wealthy countries and early childhood development, the U.S. came in as "falling behind" in the report. Sweden came in on top.
The Save the Children report card shows that D.C. came in at No. 42 on a national list of fourth-graders reading below their level. Virginia came in 13th and Maryland did best locally at No. 8.