The High School Musical star, 38, was full of smiles as he held their sweet little sister, Olivia, 5, on his lap during the show.
DWTS fans had been hoping Zac would pop up in the audience or backstage for weeks, and now they finally have their wish.
Dylan, 33, and pro partner Danielle Karagach danced to Zac and Zendayaâs song Rewrite the Stars from film The Greatest Showman.
His dance was dedicated to their sister Olivia who wore a sweet pink dress while watching the live competition.
Dylan said in a recording before the show: âIâm dedicating this dance to my little sister, Olivia.
âI wasnât expecting to be a big brother but immediately, I was inseparable from her.
âNow, being able to dance to âRewrite the Stars,â this is a nod to my brother.â
Becoming emotional, he added: âZacâs always taken care of me and he did things that were so selfless. I wanna be that to Olivia, I wanna be the best role model I can.â
Fans rushed to social media to voice their excitement on Zacâs appearance and one wrote: ââWhen I tell you I screamed when Zac Efron popped up on my screen.
âHim being there along with his and Dylanâs sister Olivia got me shedding a tear.â
Another said: ââIâm cracking up yâall bullied Zac Efron to the ballroom.â
While a third exclaimed: âZac Efron is in the house!â
Dylan previously told People that it was his mom Starlaâs dream 20 years ago for his older brother to compete in Dancing with the Stars, and sheâs thrilled heâs now doing it.
She has been in the stands throughout the competition, along with his dad, David, and other siblings.
Dylan recently admitted he was always conscious of Zacâs career growing up and never wanted to do anything to mess it up.
During an episode of the Therapuss podcast, he said, âIâve been hyper-aware of how I present myself and stuff like that from a young age.â
He was a freshman when High School Musical premiered in 2005, and he remembers being supportive of his older sibling.
Zac has always been supportive of his brother stepping into the limelight and following in his footsteps as a celebrity.
Dylan previously appeared on reality show Traitors, and was declared one of the four winners alongside Gabby Windey, Dolores Catania, and Lord Ivar Mountbatten.
During the explosive season, Zac told E! Newsâ The Rundown, âI hope he does [win] because heâs so good at games. He always has been since we were kids. Heâs like the game master.
âI donât care what game it is. It can be a luck game like Yahtzee and he always gets Yahtzee on the first roll.â
He added, âIf anyone can do this, itâs him. Iâm rooting for him.â
Dylan is best known for producing episodes of Netflixâs Down to Earth with Zac and was a production coordinator on 2018âs Ready Player One.
He also worked as an assistant on Get Hard starring Will Ferrell and Kevin Hart, along with A Star Is Born with Lady Gaga and Bradley Cooper.









