For friends, family and fans of the late Paul Walker, this is always a somber time of year. Walker would have turned 44 on Tuesday, and those closest to him are sharing their bittersweet memories of the late star to commemorate the day.

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Walker's daughter, Meadow Walker, shared a sweet throwback photo of herself and her dad when she was a little girl as well as a challenge from the Paul Walker Foundation.

"In honor of my dad's birthday today, we're challenging you to DO GOOD!" she wrote. "Share a video or photo of your random act of kindness and nominate 4 people to join the challenge! Be sure to tag the foundation as well as hashtag #PWFdogoodchallenge, so we can check out all of your posts!"

One of the people Meadow tagged was Walker's longtime close friend, Vin Diesel, so we can't wait to see how he pays it forward.

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On Walker's birthday, his She's All That co-star from nearly 20 years ago, Freddie Prinze Jr., gave a new interview and was of course asked about the late star. Prinze became emotional telling a story about when Walker landed that role.

"When Paul came in to audition, I didn't have cast approval, but I had what they called consultation," he remembered. "I knew Paul was the right guy, and when he finished the audition, I asked if I could excuse myself to go to the bathroom. I ran outside to where his car was parked. I said, 'Hey man, you're gonna get this job.' They didn't pay us anything. It was a small movie. [I said], 'They're gonna offer you $25,000, they have $75 in the budget. Don't say no.'"

After Walker's death three years ago, Prinze found out that Walker had told that story to his brother and mom. "To hear that, that meant a lot to him to share that. I loved that there was still that connection there," he said.

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Walker was killed in a car accident in 2013. Since then, his family and friends have kept his legacy alive, and this week is no exception.