8th Annual Tribeca Film Festival - "Moon" Premiere
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“8th of Jan again. A strange feeling for me,” Duncan Jones tweeted on what would’ve been the 71st birthday of his father, David Bowie.

The legendary singer known as Ziggy Stardust died from cancer just days after he turned 69 in 2016. On Monday, Jones, 46, commemorated the birthday anniversary by resharing an old sketch he posted to mark the birth of his son, Stenton David Jones.

“I know how excited dad was to have a grandson on the way, & I made this card for his birthday having told him a month earlier he was going to be a [granddad],” the Warcraft: The Beginning director explained. “Makes me smile at our shared goofy sense of humour. Happy birthday dad!”

Stenton was born on July 10, 2016 — six months after “his granddad made room for him,” Jones had wrote at the time. The filmmaker continues to keep the memory of Bowie alive since he passed away surrounded by his family.

“I lost my dad last year, but I also became a dad,” Jones said while accepting the BRIT Awards’ posthumous honor for Bowie last year, “and I was spending a lot of time after getting over the shock of trying to work out what would I want my son to know about his granddad.”

He continued: “And I think, it would be the same thing that most of my dad’s fans have taken over the last 50 years: he’s always been there supporting people who think they’re a little bit weird, or a little bit strange, a little bit different. And he’s always been there for them.”

An early demo of “Let’s Dance,” the title track of Bowie’s 1983 album, was also released on Spotify to mark the anniversary. This marks the first time the demo has been released in 35 years since Chic founder Nile Rodgers mixed it.

“I’ve always called him ‘the Picasso of rock & roll,’” Rodgers had told EW hours in 2016. “It always embarrasses him, but I say it to his face in public, anytime we’re with people.”

Listen to the track above.