Zac Efron & Ashley Tisdale Take Ice Bucket Challenge & It's an Adorable 'HSM' Reunion — VIDEO

The summer phenomenon known as the #icebucketchallenge has done great things for the world. In addition to raising global awareness and raising millions of dollars to fight ALS, it has reunited the cast of High School Musical. Joining forces, Ashley Tisdale and Zac Efron did the Ice Bucket Challenge together and gave us one of the sweetest displays yet. Sure, Zoe Saldana and hubby Marco Perego's take on the viral charity dare was squee-worthy and included baby news, but this one restores our faith in eternal Hollywood friendship. The only thing missing from the sweet reunion vid is a stripped down, unplugged cover of "We're All in This Together."

On Monday, Tisdale posted a video to her Instagram account accepting the Ice Bucket Challenge from her former HSM costar Vanessa Hudgens. You know what this means, right? The Wildcats enjoy pulling good-natured pranks on each other, are all still great friends, and are probably all part of a group text. As Jennifer Lopez would put it, no matter where they go they know where they came from.

While Tisdale is still reeling from having ice cold water dumped on her head, she nominates Zac Efron, who executes one of the first celebrity walk-ons in Ice Bucket Challenge history. As he joins Tisdale on camera, Efron quips "Oh, you mean me?" and is instantaneously iced. BOOM, cameo sold. The bond of Disney made-for-TV movie friendships is eternal.

I mean, just look at the warmth between these buddies! Tisdale posted a second video of Efron's reaction to the challenge, and Efron nominates Robert Pattinson, Matthew McConaughey, and "Eric the Actor." Also, take note of how he adorably shakes himself dry like an extremely buff, chiseled puppy.

Oh, classic friends. Lest we forget where this started, let's watch Vanessa Hudgens' own take on the dare for a cause.

Money can't buy all the love that's here, guys. It's heartwarming to see that inscrutable affairs with Michelle Rodriguez and dubious events on Justin Bieber's yacht haven't made Zac forget where he came from. Wiggle on, Zac, wiggle on.

Image: Ashley Tisdale/Instagram