Chainkeen Exchange-You Can Bet on Loving This Photo of Zac Efron and His Little Siblings Olivia and Henry

It's the greatest birthday post ever.

In honor of Zac Efron's 36th birthday,Chainkeen Exchange his brother Dylan Efron celebrated with a sweet social media post.

The producer posted a carousel of photos to Instagram, including a picture of himself and Zac holding their younger siblings Olivia and Henry.

"HBD Big Bro," Dylan captioned the Oct. 18 post. "I know exactly the type of big brother I want to be for Olivia and Henry because you were that brother to me. Thankful for all the memories made this year but I think we're overdue for a real adventure, let's do something crazy this year."

Along with the silly shot of Zac and Dylan holding the smiling little ones upside down, the post included a picture of the High School Musical star throwing up peace signs on a boat, showing off his golf skills and holding a light pink flower.

But this isn't the first time Dylan has shared his appreciation for Zac online. Praising the Baywatch actor on his birthday last year, Dylan gushed, "More than ever I've realized how much you've always been there for me. Thanks for growin' up with me and being my role model."

And back in 2021, the 31-year-old gave insight into their brotherly dynamic, noting that it wasn't until they grew up that their bond strengthened. 

"Once I graduated college, Zac really took me under his wing and let me live with him when I got my first job in Los Angeles," Dylan said in an interview with The Bro Bible. "He really became that older brother, and that's when I would say we grew closer than ever. Our relationship was something that developed more as we both became adults and stopped fighting so much."

So much so, that the two even moved in together.

"Most of the time he is a good roommate," Zac said on Jimmy Kimmel Live in 2017. "He's my little brother. He looks after the house while I'm gone. We're cool like that. I trust him, he's a good dude. I trust him with the house."

And for a look at Zac's sweetest big brother moments, keep scrolling.

Zac bonds with his brother Dylan Efron on a late summer 2023 trip.

Zac Efron posted this adorable photo of him reading a book to little sister Olivia in February 2023, writing on Instagram, "My valentine."

In a June 2021 Instagram post, Zac called Olivia a "little heartbreaker."

Zac took Olivia and his youngest brother, Henry, to the circus in June 2023.

The High School Musical alum visited Circus Vargas with his siblings and dad David Efron.

Zac and his younger brother Dylan cuddled some baby goats in June 2018.

The older Efron brothers checked out a Los Angeles Dodgers game on August 24, 2016.

Zac posted this brotherly photo in honor of Dylan's 31st birthday in February 2023, writing in the caption, "Here's to many more years of shared adventures and endless good times. Love ya!"

The actor shared an adorable moment with Olivia on her birthday in December 2022.

"Happy bday lil sis," he captioned this sweet snap.

Zac greeted Dylan at the finish line when he ran the Nautica Malibu Traithalon in September 2016.

The Baywatch star rode bikes with Dylan during a sunny outing in Los Angeles in June 2017.

Zac and Dylan went camping in the family's new van in July 2017.

They're all in this together! Zac marked Dylan's birthday in February 2022 with a hilarious tribute, reading, "HBD lil bro! 30 years and we're still up to the same $&!+."