Michael J. Fox celebrates lookalike son Sam's birthday with rare ...

Happy birthday Sam Michael Fox! The oldest of Michael J. Fox and Tracy Pollan's four children officially turned 35 on May 30, and his parents are in celebration mode.

Sam is an actor just like his parents, although prefers to keep his life out of the spotlight in the vein of his siblings. His younger siblings include twins Aquinnah and Schuyler, 29, and youngest Esmé, 22.

Earlier on Thursday, Michael, 62, sweetly took to social media with a photo of Sam blowing out the candles on his chocolate cake, covered in icing flowers, and looking so much like his famous dad.

The Back to the Future star penned: "Sam, what a trip it's been. From the boy who had questions about everything to the man who has so many answers and still more questions." 

"I love you. Oh yeah, thanks for all the laughs. You are my best friend and only son. Happy birthday!" he concluded, receiving a barrage of wishes also from celebrity friends like Ali Wentworth, Justin Long, Kate Bosworth, Jennifer Grey, and more.

Tracy, 63, took to Instagram as well with a pair of photos, one a throwback of a young Sam displaying his more playful side, and the other with his mom at the beach. "Happy birthday to my absolute favorite partner in crime! I love you so much — Have the best birthday."

Sam, like the rest of his siblings, shares an extremely close bond with his parents, stepping out to support them for events and red carpets from time to time. In February, he even announced on Instagram that he'd gotten engaged to longtime girlfriend Molly Milstein. He is also a producer, most recently working on his dad's documentary film Still: A Michael J. Fox Movie. Watch the trailer below...

In a previous interview with Reader's Digest, Michael shared his parenting advice, which was: "Always be available to your kids. Because if you say, 'Give me five minutes, give me 10 minutes,' it'll be 15, it'll be 20. And then when you get there, the shine will have worn off whatever it is they wanted to share with you."

Speaking previously with Good Housekeeping, the Family Ties star explained that despite his battle with Parkinson's disease, his family members have been his biggest champions, and all of them have stepped up to the plate when it comes to adapting to tough situations and advocating for the disease.

He spoke fondly of familiar family rituals, saying: "We'll go up to the country. And it's not unusual to make popcorn and then for all six of us to climb into bed and watch TV — just bodies everywhere. We are a really affectionate family, and we laugh a lot." 

He added: "And you know, with Parkinson's, my kids just make the transition. If I am reaching for something, they will just do it and carry on."

"Sometimes I'll stop and think, 'Am I selling short the experience my family is having?' But then I'll look back at it and say, no — they're having fun."