Australia - Millions of Twitter users are wondering what happened to Zac Efron's face after the actor's appearance in a promotional video showed some big changes.

During a Facebook livestream to honor Earth Day, former Disney star Zac Efron spoke with host Bill Nye and other participants about Earth Day and called for more care for the planet.

But somehow, the topic of environmental protection and sustainability was quickly forgotten at the sight of the 33-year-old.

Shortly afterwards, numerous screenshots from the video circulated on Twitter, with people wondering aloud what happened to Zac's face.

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Many users agreed that they had found the all-important clues, with his lips, jawline, and especially chin reportedly looking completely different.

They claimed that the actor had been injected with A LOT of beauty fillers to accentuate various parts of his face.

Zac Efron has yet to comment all this social media commotion.

But maybe he doesn't need to, because countless fans came to the star's defense! They stressed that the video in question is meant to focus on protecting the planet, not the Hollywood star's appearance.

People also pointed out that Efron had previously had some serious health. In an interview with Men's Health, he confessed that he struggled with alcohol problems for a long time. Fitness helped him out of the crisis at the time. "Just leave him alone," one user wrote.

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Clearly, Zac Efron can count on his fans to always stick up for him.

He doesn't really have time to respond to the wild speculation anyway as he's currently filming the second season of Around the World with Zac Efron, which will be released on Netflix.

Anthony Youn, a plastic surgeon famous for his work on celebrities, even chimed in on TikTok to say that he actually thinks Efron's swollen face is the result of a recent dental surgery, and not at all from cosmetic fillers.

Only time will tell if the actor's new look is temporary or permanent.