TAIPEI, June 12 — When two of Mandopop’s biggest names casually decide to share a microphone, the internet doesn’t exactly stay calm.

Fans were sent into meltdown mode this week after Jay Chou and JJ Lin teased — and swiftly delivered — an unexpected musical collaboration.

It all started when Jay, 46, posted a photo with the Singaporean singer on Instagram on Tuesday, revealing that JJ would be covering one of his latest songs.

“Which of my new songs would everyone like to hear JJ Lin cover? Stay tuned tomorrow at noon!” Jay wrote, referring to JJ by his fan-bestowed nickname, the “walking CD” — a nod to his reputation for sounding just as flawless ‘live’ as he does on record.

The cryptic post immediately triggered a wave of speculation, with fans trying to guess which track would get the JJ treatment.

Some eagle-eyed followers pointed out that JJ had previously hummed part of Jay’s recent release It Rained That Day during a livestream, fuelling suspicions that the duo had been planning something behind the scenes.

Others wondered if the photo had been snapped during filming for Jay’s travel variety series J-Style Trip, given the pair’s long-standing friendship and habit of popping up in each other’s projects.

As it turned out, fans didn’t have to wait very long for answers.

Later that same evening, JJ uploaded a video of the two stars singing a portion of It Rained That Day together.

“Lovin’ the duet vibes – jamming with the GOAT,” JJ captioned the clip.

The short video was enough to send fans into overdrive, with many praising the effortless harmonies between the Mandopop heavyweights.

But admiring the vocals quickly turned into demands for something bigger.

Calls for a proper collaboration flooded the comments section, with fans pitching everything from an original duet to a full-blown joint concert.

“When can we see them perform together again?” one fan asked, while another joked: “When are you two releasing a song together? I’ve waited so long my hair has turned white.”

A third summed up the collective mood with a simple request: “Give us a JJJay concert!”

Others were just excited by the prospect of seeing more of the duo’s chemistry on the upcoming season of J-Style Trip.

The surprise appearance was so unexpected that one fan admitted to spending “five seconds checking if they were the real ones”.

In fairness, that’s not entirely unreasonable. The singers’ celebrity lookalikes had previously gone viral online for staging their own unofficial “collaboration”.

This time, though, the real Jay and JJ showed up — and fans are already hoping it’s only the opening act.