Meadow Walker launched her annual "Do Good Challenge" in honor of her late father Paul Walker's birthday this weekend.

The 21-year-old shared a tribute for her father, who died in 2013, to mark what would have been his 47th birthday on Saturday.

Alongside an old snap with her dad, Meadow wrote, "The moment I realized we are twins. Happy birthday to the most beautiful soul."

The "Do Good Challenge," which Meadow leads with her organization, the Paul Walker Foundation, calls for people to do an act of kindness and share it with the world.

"Doing good goes both ways, this challenge we'd like you to keep in mind that whether you're doing good for others, being good to yourself is also important," the Paul Walker Foundation detailed in a post launching the challenge.

Meadow kicked off the challenge by sharing a post with a friend, in which she reflected on the good people she has in her life.

"I’m keeping it simple and close to my heart," she captioned her post. "I am so blessed to be in love with my best friends."

"Thank you Diva and Morgan for working on this project with me to capture a snippet of our friendships," she added. "My friendships are my foundation. They are my family. Tell your friends you love them and acknowledge them for standing by your side no matter what. #DoGood #BeGood."

Meadow then tagged several people on her post in hopes they will continue spreading the challenge on social media.

See more tributes shared for Paul Walker on his 47th birthday below:

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A post shared by Vin Diesel (@vindiesel) on Sep 12, 2020 at 5:09pm PDT

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I miss you.

A post shared by jordanabrewster (@jordanabrewster) on Sep 12, 2020 at 9:12am PDT