"This is most nervous I've ever been in my entire life," Sivan said in the clip. "It feels kind of weird to have to announce it like this on the Internet, but ... this is not something that I'm ashamed of, and it's not something anybody should have to be ashamed of, so why not share it with all of you guys?"
Sivan said he came out to his family on Aug. 7, 2010. He explained that his whole life, he knew he wasn't like other boys.
"When I was born I always knew something was a little bit different about me," he said.
Ultimately, Sivan said he hoped his video would provide hope for other gay and bisexual people, just the way he found comfort in YouTube confessions made by others when he was younger.
"Those people on YouTube, those brave, brave people on YouTube, without them, I don't really know where I'd be," he said.
Click the video above to watch a clip from Sivan's confession, or watch the full video on his YouTube page.