The star's daughter called her mom an "inspiration" along with the women pioneering the movement.
Reese Witherspoon's daughter is happy to support her mom as she helps lead the Time's Up movement.
In an Instagram post on Sunday before the Golden Globes, her daughter, Ava Phillippe, shared a heartfelt message about her mom's work.
"Thank you to my inspiration of a mother and to all the women paving the way for those who face these abuses of power," she wrote in the caption for an image showcasing the Time's Up mission statements.
"I see how hard these women are working to unite people of various backgrounds and to institute real, lasting change, and I am so proud of what they have and will accomplish," she continued.
The 18-year-old went on to encourage anyone reading the message to make a donation to the initiative, which has reached its initial $15 million goal for a legal defense fund to help women protect themselves from sexual misconduct, as well as seeking legislation to penalize companies that turn a blind eye to harassment.
"And you can also wear black today in solidarity! Time’s up," she concluded, referencing the actresses who will be wearing black on the red carpet at the Golden Globes.
In addition to wearing black, Witherspoon, along with other actresses who joined forces to start the movement, will be sporting "Time's Up" pins. The 41-year-old commissioned the pin, and 500 were manufactured, according to The Hollywood Reporter.
For more on the Time's Up movement, watch the video below.
Reese Witherspoon Is Responsible For the Time's Up Pin Everyone Will Be Wearing at the Golden Globes
Golden Globes 2018: Meryl Streep, Emma Watson and More Escorting Time's Up Activists to Awards Show