Zac Efron And His Brother, Dylan, Flaunt Tight Abs As They Frolic In Waterfall

Christopher PolkGetty Images for MTV

When actor Zac Efron wished his younger brother, Dylan Efron, a happy birthday on social media, it was his fans who received the greatest gift of all — four hot photos of the sexy siblings frolicking in a waterfall in only their swim trunks.

The 31-year-old star of the Greatest Showman posted the priceless pics on Instagram on Wednesday, February 6, which was Dylan’s 27th birthday. In the four-image slideshow, the brothers are posing for the camera in the plunge pool at the bottom of a heavily flowing waterfall. They are both wearing long board shorts — Dylan in sky blue and Zac in black with red and white accents — and, since they are both sans shirts, their rock-hard abs are on full display.

In the first snapshot, Dylan, who is the taller Efron, has his arm around Zac’s neck as if he’s choking him. The Baywatch star played along with his little bro by sticking out his tongue.

In the second shot, Dylan still has his arm wrapped around Zac’s neck, but he has loosened his grip a bit. With his other arm, the younger sibling is flexing his muscles, and his big bro does the same with both of his limbs. The Efron boys are both smiling as they show off their muscular physiques.

Photo No. 3 features four-years-younger Dylan trying to dunk Zac in the water, and, in picture four, fans see that the actor has gotten away from his mischievous brother.

Zac did not reveal where the playful pics were taken, but the hunky brothers definitely had a great time that day.

In his touching caption, High School Musical’s Troy Bolton said that he never thought that “the little terror, devil, monster that was [his] little brother would turn into [his] very best friend.”

“I’m so proud of the man you are today. Let’s save the world together — one waterfall at a time.”

The post on Instagram has been liked more than 2.1 million times in just six hours online. Fans of the studs also left more than 10,300 comments, including many heart eyes emojis.

One notable comment came from Zac’s Extremely Wicked, Shockingly Evil and Vile co-star Lily Collins, who also wished Dylan a “Happy birthday.”

The birthday boy did leave a response to his brother’s public message that simply said, “Love you brotha.” He devilishly added the smiling face with horns emoji.

In the bio on his Instagram page, Dylan says that he is a filmmaker, writer, athlete, and outdoor enthusiast. He has worked as an assistant to producer Ravi D. Mehta on the films Unforgettable, Chips, and Get Hard, per IMDb.

Meanwhile, Zac has been earning rave reviews for his portrayal of serial killer Ted Bundy in Extremely Wicked, Shockingly Evil and Vile, which premiered at the Sundance Film Festival in Park City, Utah, on January 26. At the fest, he also debuted a platinum blond hairstyle, as previously reported by the Inquisitr.