Shawn Mendes just made one of his dreams come true. The singer who has been a John Mayer for quite some time surprised fans when he made a guest appearance during one of the "Still Feel Like Your Man" singer's tour stops in Toronto.

The "Stitches" singer left fans shocked when he walked on stage at the Toronto's Air Canada Centre
for a mashup of his hit song "Mercy" and John's "In Your Atmosphere." Shawn started off singing an acoustic version of his jam and then they transitioned into the second song.

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Shawn shared a photo of the moment on Instagram with the caption, "Thank you so much @johnmayer."

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Thank you so much @johnmayer

A post shared by Shawn Mendes (@shawnmendes) on

John shared a photo where Shawn is all smiles with a caption saying: "The dynamite @shawnmendes joined me in Toronto tonight perform a "Mercy"/"In Your Atmosphere" mashup and it was over the top good. #thesearchforeverything #shawnmendes #bringingbacktheworddynamite"

Shawn gave a more emotional statement on Twitter about the magical night saying, "Damn. John Mayer is the best. My job is the best. U guys are the best. What an insane night. ❤️"

After the show, John jumped on Instagram for an Instagram Live stream with his fans and he sang Shawn's praises in front of his many followers.

"You're very welcome for the performance with Shawn. It was the right time. It was the right time. What a great kid. What a great singer. And just so you know, your favorite artist Shawn Mendes for those who are watching who are Shawn Mendes fans should know that not only is he one of the nicest people around but when we started working out this mashup together he had the quality that I love in musicians," he said.

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"He was incredibly confident. Incredibly confident about how to work the song out, what the notes should be, where we should go with it and was adamant about running it and getting it right. And that's a pro. So he is a PRO. He came out and it was phenomenal." SO CUTE!

The two guys were not the only ones blown away by their collaboration as fans, including Shawn's good friend Camila Cabello, freaked out when they heard the news.

Camila who knows how big of a fan her friend is tweeted at him saying: "u performed with John Mayer last night…. R U EVEN ALIVE OMG."

A fan from Canada wrote: "Im still hyped about the john Mayer and Shawn mendes performances !!! Beautiful harmony between thoses two legends !!! Wow , blown away !!"

Another fan flipped the switch and said that it was John who was actually the one fan-girling. She wrote: "I feel like John Mayer is a huge fan of Shawn Mendes."

An eager fan wrote that after seeing that wonderful mashup between them, they now kind of owe the world a duet.

There is no denying that these two's voices sound fantastic together and cannot wait to see them back on stage again in the future. Watch the performance below.

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