Zac Efron celebrates his brother's birthday on Instagram

In case you weren't already aware, there is a second Efron brother. I repeat: there is a second Efron brother, meaning all of that talent and all of those good looks were handed to not one, but two men.

If you've never heard of Dylan Efron, here are a few facts to get you started. He is a 27-year-old former economics student who eventually followed his famous brother into show business scene, working as the assistant to producer Ravi Mehta on films Get Hard, CHIPS and Unforgettable.

He's also a sports fanatic, who documents his dedication to fitness and exercise on an Instagram page you'll probably want to follow immediately.

Another fact you'll be keen to know is that it was his birthday this week.

Zac gave a heartwarming birthday shout-out to his little bro on social media on Wednesday, naming Dylan his "very best friend".

However, it was the picture he uploaded that many fans were more interested in. The actor's followers were thrilled when he uploaded several photos of them both topless, playing around in a waterfall.

"Happy birthday @dylanefron!" he wrote. "Honestly, I never in my wildest dreams, would’ve thought that the little terror, devil, monster that was my little brother would turn into my very best friend. I’m so proud of the man you are today. Let’s save the world together- one waterfall at a time. Love ya little brother!"

People online loved the post, with many of them taking to the comment section to wish the younger Efron a happy birthday. Others drank in the photo, with one person on social media writing: Someone should probably tell Zac Efron not to thirst trap with his brother...but it’s not going to be me."

"I just want to thank the parents of Zac and Dylan Efron for making such masterpieces," another fan wrote. "What an incredible job on these two creatures. Thank you for blessing this world with art."

Unfortunately, the younger Efron’s big day wasn't all fun, games and waterfalls though, starting off with some car troubles. Dylan posted a photo on his own Instagram account of his vehicle getting towed in Mammoth Lakes, California, writing that it wasn't the celebratory morning he had in mind.

"Happy birthday to me," he joked. "Wasn’t the morning I had in mind but incredibly thankful for all the nice texts and people who reached out today! Special thanks to Billie Lozano for fixing up The Wolf and making me laugh in the process."

The internet first became aware of the 27-year-old's existence a few years ago when Zac posted an adorable picture of him getting a piggyback from his bro on social media. Since then, the pair have blessed us with several photos of their adventures, hikes and travels around the world together.

In an interview with Cosmopolitan in 2017, Zac spoke out about their brotherly bond, claiming that he often looked to his younger sibling for dating advice.

"If I’m dating someone, one of the few people I need to weigh in on the situation is my brother," he said. "We live together, and we’re different in a lot of ways, but he’s really grounded. He lived a more normal life than I did growing up, so he’s a great barometer for me. He’ll be like, 'Are you sure you’re happy? Is this what you really want?' Having my little brother around is a really great thing."

Awww! Those Efron boys!