Shawn Mendes collaborates with Ed Sheeran on his song Mercy in New York - watch

Imagine heading off to a Shawn Mendes gig and being surprised with an Ed Sheeran collaboration? Well fans in Brooklyn last night didn't need to imagine. It actually happened.

The 19-year-old Canadian surprised his screaming legion of fans by bringing out Official Chart mainstay Ed Sheeran to duet on Shawn's song Mercy, a Top 20 hit from last year, at the Barclays Center in Brooklyn. 

Each with a guitar in hand, the two delivered an epic performance, a serenading moment captured by the Barclays Center's official Twitter account, and many fans in attendance. Watch the performance below:

🚨 HAVE MERCY. @edsheeran IS HERE. @ShawnMendes #ShawnBKLYN #IlluminateWorldTour pic.twitter.com/XBDrSbELdK

— Barclays Center (@barclayscenter) August 17, 2017

Shawn sang with his one of his biggest idols tonight to his own song, SHAWN AND ED DID THAT pic.twitter.com/zfApAZ51o6

— aubrey (@nopromisesmndes) August 17, 2017

hello everyone needs this video of Shawn Mendes and Ed Sheeran singing Mercy together on their timeline pic.twitter.com/8AXlGA6SAP

— ㅤㅤkc (@mainlymendes) August 17, 2017

Clearly there is a lot of mutual respect between the two chart toppers, but the moment was perhaps even sweeter for Shawn. In 2014, he tweeted:

The goal is to go on tour with ed sheeran.. Thats the goal * dream

— Shawn Mendes (@ShawnMendes) April 8, 2014

Mission accomplished.

Both Shawn and Ed have already completed UK stints of their respective tours this year, while Ed has another huge UK headline tour coming up in 2018. Who knows, maybe he'll return the favour and have Shawn pop on stage? 

Ed Sheeran was also recently announced as a nominee for the Mercury Prize 2017, and is currently embroiled in a huge chart battle of the Official Albums Chart with Elvis Presley. He's a busy guy.

MORE: View Shawn Mendes' full UK chart history here, and check out Ed Sheeran's phenomenal chart past here

Image: Twitter/@ShawnAccess