The internet prank known as "Rickrolling" may be about a million years old in Internet years, but even Greta Thunberg knows a classic when she sees one.

The Swedish teen climate activist had people going absolutely wild when she trolled the crowd at a recent climate change-themed concert, treating attendees to a surprise performance of pop singer Rick Astley's 1987 hit—and beloved internet joke—"Never Gonna Give You Up."

Thunberg took to the stage at the Climate Live concert in Stockholm to sing and dance to the iconic song.

See a clip below.

At first when Thunberg took the stage, she appeared to be preparing to deliver another of the rousing speeches about climate change that she has become famous for--like the one a few weeks ago when she called out Democratic U.S. President Joe Biden and U.K. Prime Minister Boris Johnson for their inaction on the crisis.

But instead of launching into missives about fighting climate apocalypse, Thunberg delivered words that will seem instantly familiar to anyone who's spent time on the internet over the years:

"We're not strangers to love..."

A fellow activist onstage chipped in the next line of Astley's hit:

"You know the rules, and so do I..."

And suddenly the song came bursting out of the sound system as the crowd erupted into an ecstatic song and dance.

The "Rickroll," a long-running internet joke that first began on April Fool's Day 2007, involves a bait-and-switch prank where internet users follow a hyperlink purporting to be relevant to the topic at hand, but instead leads to Astley's deliciously cheesy 80s pop video.

But if you think Astley's feelings might be hurt by all this, think again.

Even he took to Twitter to praise Thunberg's stunt as "fantastic."

Speaking to Swedish newspaper Aftonbladet, the usually serious Thunberg explained why she incorporated a Rickroll into her Cliamte Live appearance:

"At the end of the day, we are just teenagers fooling around with each other, not just the angry kids the media often portrays us as."

On Twitter, people absolutely loved it.

This isn't the first time Thunberg has Rickrolled us.

She previously used the trick in an April Fool's Day tweet this year offering climate change activism guidance, but led to Astley's video.

Good on her for having an appreciation for the internet classics!