Troye Sivan may be a burgeoning pop star, but rest assured, he still fan girls just like the rest of us.

During his appearance on the Late Show With Stephen Colbert on Thursday (Sept. 6), Sivan revealed that he was so nervous for his guest performance on Taylor Swift's Reputation tour that not only did he feel like he was "tripping on acid," but straight-up almost fainted onstage.

"I was like, oh my God, I'm going to fall over and pass out in front of all of these people," he explained.

Apparently, the whole thing came about because Sivan, who is a noted Swiftie, wanted free tickets to Swift's show and, naturally, reached out to see if his growing ~status~ was enough to swing them. To his surprise, Swift responded yes — but only if he'd sing with her onstage.

"I was completely floored by this, freaked out, but I was like, this is my way to get free tickets so I'm going to do it for sure," Sivan told Colbert.

But when the time came for him to pop out of a trap door and perform in front of 60,000 people, he froze.

"I looked out and I was like, this is more people than I've ever seen in one place," he continued. "Honestly, I started to feel really faint."

Sivan went on to say that he tried to look at his feet to ground himself, but as Swift's stage design includes flashing, LED-screen floors, it only worsened things.

"I was like, I'm 100 percent tripping on acid right now. This is insane."

He then decided to look at the person next to him, rather than the massive audience, which again backfired, because that person was Taylor Swift.

"I looked at her and I was like, 'Oh my God that's Taylor Swift.'"

Eventually, though, Sivan pulled it together and started strutting, which he said finally calmed him down.

Watch the full story in the video above.

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