Robin Williams' Son Zak Marks What Would Have Been His 70th Birthday With Heartfelt Tribute

Robin died in 2014.

Robin Williams' family is honoring his legacy on what would have been his 70th birthday. The late actor's son Zak took to Instagram on Wednesday to share a heartfelt message, assuring his father's "incredible spirit lives within us."

Zak is Robin's son from his first marriage to Valerie Velardi in 1978. The actor was also dad to daughter Zelda and son Cody from his marriage to Marsha Garces. He married his third wife, graphic designer Susan Schneider, in 2011. 

"Dad, on what would be your 70th birthday, I would want you to know that your incredible spirit lives within us," Zak wrote on Instagram on Wednesday. "Our family will be celebrating you and your memory today. We miss you and love you always!"

To honor what would have been Robin's 69th birthday last year, Zelda shared her plans to give back to those in need. Robin was one of the founders of Comic Relief USA, and the nonprofit raised millions of dollars for homelessness causes in the United States over its 25-year run.

"Today would’ve been Dad’s 69th birthday, so to honor him (& that glorious number), I will be donating $69.69 to as many local homeless shelters as I can," Zelda wrote on social media. "Join me if you like, but regardless, know I am wishing you all at least one hearty, immature belly laugh on Dad today."

She then shared screenshot receipts from all of her donations, which included funds to Los Angeles– and San Francisco–based LGBTQ centers, Midnight Mission, Union Rescue Mission and more organizations. "Gonna go back to being off socials for awhile (as I do yearly)," she concluded her thread, "but thanks for joining me in honoring Dad (and the number 69) today! ... it was ‘nice.’"

Robin died by suicide in August 2014, a year after he was diagnosed with Parkinson's disease. In a September interview with the Today show, Robin's widow, Susan, said he died of diffused Lewy body dementia, a disease that can lead to problems with thinking, memory and movements.

See more on Robin in the video below.