In just two short years Shawn Mendes has gone from Vine star to pop star.

The "Life of the Party" singer skyrocketed to the top of the charts with his debut album Handwritten, is an opening act on Taylor Swift's 1989 World Tour and just recently played his first-ever sold-out headline arena show.

Not too bad for a 16-year-old.

In between opening for T. Swift, Shawn has been headlining his own tour, #ShawnsFirstHeadlines, and on the June 7 stop at Connecticut's Mohegan Sun, he marked a personal milestone.

"Playing in a sold-out arena filled with my fans was one of the most unreal experiences," Shawn exclusively told MTV News. "I can't believe how many people came out to the show, and how many were singing along to every word of every song. Thank you so much to my amazing fans."

In a behind-the-scenes video from the show, Shawn's gives us a glimpse at the build of the stage, the moment he takes the stage and the 8,000 fans on hand seeing him in action.

"It looks unreal and I can't believe it. It's funny I found out a couple of days ago that I was doing a show this big," he said in the clip. "I didn't even know we sold this many tickets for a show and it's kind of blowing me away."

While Shawn may be used to playing in venues bigger than this -- he has been performing at arenas all over the U.S. with Taylor -- the experience takes on a whole new meaning when all the fans are there just to see him.

"It's different when you are an opening act and you see an arena full of people -- it's incredible and amazing to go on stage, but it's different because I know they are all there to see me. That is just the most humbling feeling ever," he said. "I don't know how to explain it, it's surreal. The fact that I don't know when this happened, the fact that this many people wanted to see me play a show... it's so crazy to see how fast things are moving and how quickly we got to this many people being at my shows."

The excitement doesn't stop any time soon. Shawn is still on the road for his #ShawnsFirstHeadlines from now until August 16, when he wraps it up at The Greek Theater in Los Angeles. And if you're a Shawn fan, I suggest grabbing tickets for that show because he's doing something pretty special. Shawn is throwing his first live video headline concert, ShawnAccessLive, and promises there will be some special guests.